SEC Form DEF 14A filed by Zymeworks Inc.

ZYMEWORKS INC.

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

OF ZYMEWORKS INC.

AND

PROXY STATEMENT

FOR ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON DECEMBER 30, 2025

November 10, 2025

ZYMEWORKS INC.

Notice of Annual Meeting of Stockholders

The 2025 annual meeting of stockholders (the “Meeting”) of Zymeworks Inc., a Delaware corporation (the “Company”), will be held on December 30, 2025, beginning at 9:00 a.m. Pacific Time. The Meeting will be conducted virtually via live audio webcast. If you are a stockholder of record at the close of business on November 3, 2025 (the “Record Date”) you are invited to attend the Meeting virtually by visiting meetnow.global/MZKC5MK, where you will be able to listen to the Meeting live, submit questions and vote online. If you plan to attend the Meeting, please follow the registration instructions as outlined in this proxy statement.

The Meeting will be held for the following purposes as more fully described in the accompanying proxy statement:

The business to be considered at the Meeting may be considered at the Meeting or at any adjournment or postponement of the Meeting.

You are entitled to vote on the matters listed above if you were a stockholder of the Company or a holder of exchangeable shares (the “exchangeable shares”) of Zymeworks ExchangeCo Ltd., a company existing under the laws of the Province of British Columbia and an indirect subsidiary of the Company, as of the Record Date. However, you are only entitled to attend the Meeting if you were a stockholder of record on the Record Date. Street name stockholders and holders of exchangeable shares will need to obtain a valid proxy in order to virtually attend and vote at the Meeting. For ten days prior to the Meeting, a complete list of stockholders of record entitled to vote at the Meeting will be available for examination by any stockholder for any purpose relevant to the Meeting. If you would like to view the list, please contact our Corporate Secretary to schedule an appointment by calling 302-274-8744 or writing to Zymeworks Inc., 108 Patriot Drive, Suite A, Middletown, Delaware 19709.

Whether or not you plan to attend the virtual Meeting, we encourage you to read this proxy statement and promptly vote your shares. You may submit a proxy by telephone, via the Internet or by mail. For specific instructions on how to vote your shares, please refer to the section entitled “Questions and Answers—How You Can Vote” beginning on page 4 and to the instructions on your proxy or voting instruction card. Interested stockholders or holders of exchangeable shares may also contact Kingsdale Advisors at 1-855-476-7981 (toll-free in North America) or 437-561-5034 (text or collect outside North America) or by email at [email protected].

Availability of Proxy Statement Materials for the Annual Meeting of Stockholders to be Held on December 30, 2025: The Notice of Internet Availability of Proxy Materials (the “Notice”) containing instructions on how to access our proxy statement, notice of annual meeting, form of proxy and our annual report, is first being sent or given on or about November 18, 2025 to all stockholders and holders of exchangeable shares entitled to vote at the Meeting. The Notice provides instructions on how to vote online or by telephone and includes instructions on how to receive a paper copy of proxy materials by mail. The proxy materials and our annual report can be accessed as of November 10, 2025 by visiting https://www.envisionreports.com/ZYME.

Unless the context otherwise requires or unless otherwise expressly stated, all references in this notice and the accompanying proxy statement to “Zymeworks,” the “Company,” “we,” “us” and “our” (i) for periods on or prior to October 12, 2022, refer to Zymeworks BC Inc. and its subsidiaries and (ii) for periods on and after October 13, 2022, refer to Zymeworks Inc. and its subsidiaries. Similarly, unless the context otherwise requires or unless otherwise expressly stated, all references in this notice and the accompanying proxy statement to common stock or common shares (i) for periods on or prior to October 12, 2022, refer to common shares of Zymeworks BC Inc. and (ii) for periods on and after October 13, 2022, refer to common stock of Zymeworks Inc.

TABLE OF CONTENTS

i

ii

QUESTIONS AND ANSWERS

Proxy Materials

Why am I receiving these materials?

Our board of directors (“Board of Directors”) is furnishing these materials in connection with our virtual Meeting to be held on December 30, 2025. This proxy statement is furnished in connection with the solicitation of proxies by or on behalf of management and the Board of Directors. This proxy statement is designed to assist you in voting your securities and includes information that we are required to provide under the rules of the U.S. Securities and Exchange Commission (the “SEC”).

The Notice of Internet Availability of Proxy Materials (the “Notice of Internet Availability”) containing instructions on how to access this proxy statement, the accompanying notice of annual meeting and form of proxy, and our annual report, is first being sent or given on or about November 18, 2025 to all stockholders and holders of exchangeable shares of record as of the close of business on November 3, 2025 (the “Record Date”). The proxy materials and our annual report can be accessed as of November 10, 2025 by visiting https://www.envisionreports.com/ZYME. If you receive a Notice of Internet Availability, then you will not receive a printed copy of the proxy materials or our annual report in the mail unless you specifically request these materials. Instructions for requesting a printed copy of the proxy materials and our annual report are set forth in the Notice of Internet Availability.

Why did I receive a Notice of Internet Availability instead of a full set of proxy materials?

In accordance with the rules of the SEC, we have elected to furnish our proxy materials, including this proxy statement and our annual report, primarily via the Internet. As a result, we are mailing to our stockholders and holders of exchangeable shares a Notice of Internet Availability instead of a paper copy of the proxy materials. The Notice of Internet Availability contains instructions on how to access our proxy materials on the Internet, how to vote on the proposals, how to request printed copies of the proxy materials and our annual report, and how to request to receive all future proxy materials in printed form by mail or electronically by e-mail. We encourage stockholders and holders of exchangeable shares to take advantage of the availability of the proxy materials on the Internet to help reduce our costs and the environmental impact of our annual meetings.

What does it mean if I receive more than one Notice of Internet Availability?

If you receive more than one Notice of Internet Availability, then your shares may be registered in more than one name and/or are registered in different accounts. Please follow the voting instructions on each Notice of Internet Availability to ensure that all of your shares are voted.

I share an address with another stockholder, and we received only one paper copy of the Notice of Internet Availability or proxy statement and annual report, as applicable. How may I obtain an additional copy of the Notice of Internet Availability or proxy statement and annual report, as applicable?

We have adopted a procedure approved by the SEC called “householding,” under which we can deliver a single copy of the Notice of Internet Availability and, if applicable, the proxy statement and annual report, to multiple stockholders who share the same address unless we receive contrary instructions from one or more stockholders. This procedure reduces our printing and mailing costs. Stockholders who participate in householding will continue to be able to access and receive separate proxy cards. Upon a written or oral request, we will promptly deliver a separate copy of the Notice of Internet Availability and, if applicable, the proxy statement and annual report, to any stockholder at a shared address to which we delivered a single copy of these documents. To receive a separate copy, or, if you are receiving multiple copies, to request that we only send a single copy of next year’s Notice of Internet Availability or proxy statement and annual report, as applicable, you may contact us as follows:

1

Zymeworks Inc.

Attn: Corporate Secretary

108 Patriot Drive, Suite A

Middletown, Delaware 19709

[email protected]

If you are a beneficial owner of shares and you wish to receive a separate set of proxy materials in the future, or if you have received multiple sets of proxy materials and would like to receive only one set in the future, please contact your bank or broker directly.

Who pays the cost of soliciting proxies for the Meeting?

We will bear the cost of solicitation. This solicitation of proxies is being made to stockholders and holders of exchangeable shares by mail, but may be supplemented by telephone or other personal contact. We have engaged Kingsdale Advisors (“Kingsdale”) as proxy solicitation agent and will pay fees of approximately $79,860 Canadian dollars to Kingsdale for the proxy solicitation service in addition to certain out-of-pocket expenses. That firm expects that approximately 30 of its employees will assist in the solicitation. We have retained Kingsdale to provide a broad array of strategic advisory, governance, strategic communications, digital and investor campaign services on a global retainer basis in addition to certain fees accrued during the life of the engagement upon the discretion and direction of Zymeworks.

We will reimburse brokerage houses and other custodians, nominees and fiduciaries for forwarding proxy materials to beneficial stockholders and beneficial holders of exchangeable shares.

What items of business will be voted on at the Meeting?

The business items to be voted on at the Meeting are:

What are my voting choices?

You may vote:

How does the Board of Directors recommend that I vote?

Our Board of Directors recommends that you vote your shares:

2

What vote is required to approve each item?

To conduct business at the Meeting, a quorum consisting of at least 33 1/3% of the voting power of our capital stock issued and outstanding and entitled to vote must be present in person (virtually) or represented by proxy. Exchangeable shares will only count towards the quorum if they have been voted or if the holder of the exchangeable shares is represented by a proxy holder at the Meeting.

As described below, broker non-votes and abstentions will be counted for determining the presence or absence of a quorum for the transaction of business at the Meeting, but will not be considered votes cast for or against a proposal.

What happens if additional items are presented at the Meeting?

We are not aware of any item that may be voted on at the Meeting that is not described in this proxy statement. However, if any other matters are properly brought before the Meeting, the persons named as proxies will be authorized to vote or otherwise act on those matters in accordance with their judgment.

3

Where can I find the voting results?

We expect to announce preliminary voting results at the Meeting and to publish final results in a Current Report on Form 8-K that will be available on the SEC’s website at www.sec.gov and on the System for Electronic Document Analysis and Retrieval (“SEDAR+”) at www.sedarplus.com promptly following the Meeting. The Current Report on Form 8-K will also be available on our website at www.zymeworks.com.

How You Can Vote

What shares can I vote?

Stockholders

If you are a stockholder, you are entitled to one vote for each share of common stock that you owned at the close of business on the Record Date. You may vote all shares owned by you on the Record Date, including (1) shares held directly in your name as the registered stockholder and (2) shares held for you as the beneficial owner through a bank, broker or other nominee. On the Record Date, there were 78 registered stockholders holding 74,835,565 shares of common stock.

Holders of exchangeable shares

If you are a holder of exchangeable shares, you are entitled to exercise one vote for each exchangeable share that you owned at the close of business on the Record Date. You may vote all exchangeable shares owned by you on the Record Date, including (1) exchangeable shares held directly in your name as a registered holder of exchangeable shares and (2) exchangeable shares held for you as the beneficial owner through a bank, broker or other nominee. Excluding exchangeable shares held by Zymeworks CallCo ULC that were the subject of previous retractions in exchange for shares of common stock, and for which there are no voting rights under the Zymeworks Special Voting Stock, on the Record Date, there were six registered holders of exchangeable shares holding 553,184 exchangeable shares eligible to exercise voting rights at the Meeting.

What are exchangeable shares?

On October 13, 2022, we concluded a corporate reorganization under a plan of arrangement (the “redomicile transactions”). In connection with the redomicile transactions, shareholders of our predecessor Zymeworks BC Inc. (formerly Zymeworks Inc.) exchanged their common shares for either shares of our common stock or exchangeable shares issued by our subsidiary Zymeworks ExchangeCo Ltd.

The exchangeable shares were only issued to shareholders of our predecessor who made a valid election to receive these shares in lieu of shares of common stock. Exchangeable shares may be exchanged by the holder into shares of our common stock and are economically equivalent to shares of our common stock.

Holders of exchangeable shares (excluding any of our subsidiaries who may hold any exchangeable shares) are entitled to exercise one vote for each exchangeable share that they owned at the close of business on the Record Date for the Meeting (the “voting rights”). Voting rights are exercised by Computershare Trust Company of Canada (the “share trustee”) via a share of our special voting preferred stock pursuant to the terms of a Voting and Exchange Trust Agreement dated October 13, 2022 among us, Zymeworks CallCo ULC, Zymeworks ExchangeCo Ltd. and the share trustee.

What is the difference between holding securities as a registered holder and as a beneficial owner?

Most of our stockholders and holders of exchangeable shares hold their shares through a bank, broker or other nominee rather than having the shares registered directly in their own name. If your shares are registered directly in your name with our transfer agent, Computershare Trust Company, N.A., in the case of shares of common

4

stock, or Computershare Investor Services Inc., in the case of exchangeable shares (each separately and together, “Computershare”), you are the registered holder of such shares. If your shares are held through a bank, broker or other nominee, it is likely that such shares are registered in the name of the nominee and you are the beneficial owner of the shares held in street name.

How can I vote without attending the Meeting?

Whether you hold your securities as a registered holder or as a beneficial owner, you may direct how your shares are to be voted without attending the Meeting or any adjournment or postponement thereof. For directions on how to vote, please refer to the following instructions and those included on your Notice of Internet Availability or on your proxy or voting instruction card. A proxy or voting instruction card will not be valid unless completed and deposited in accordance with the instructions set out in the card.

Stockholders

If you are a registered stockholder, you may vote in the following ways:

Most stockholders who are beneficial owners of their shares and have received a voting instruction card may vote by phone by calling the number specified on the voting instruction card provided by their bank, broker or nominee. These stockholders should check the voting instruction card for telephone voting availability. Beneficial stockholders who do not object to their name being made known to us may be contacted by our proxy solicitors to assist in conveniently voting their shares directly by telephone. We may also utilize the Broadridge QuickVoteTM service to assist such stockholders with voting their shares.

Holders of Exchangeable Shares

If you are a registered holder of exchangeable shares, you may exercise voting rights by completing, signing and mailing your voting instruction card, which must be received by 2:00 p.m. Eastern Time on December 24, 2025.

If you are a beneficial holder of exchangeable shares, you may exercise the voting rights by submitting voting instructions to the bank, broker or other nominee that is the registered holder of your shares via the voting instruction card you receive. Beneficial exchangeable shareholders who do not object to their name being made known to us may be contacted by our proxy solicitors to assist in conveniently exercising their voting rights directly by telephone. We may also utilize the Broadridge QuickVoteTM service to assist such holders with exercising their voting rights.

How can I attend and vote at the Meeting?

Registered Stockholders

Registered stockholders may vote at the Meeting virtually by visiting meetnow.global/MZKC5MK. You should ensure that you have a strong internet connection wherever you intend to participate in the Meeting. Please note that Internet Explorer is not a supported browser for accessing the virtual meeting website.

5

You should also give yourself enough time to log in and ensure that you can hear streaming audio prior to the start of the Meeting. We encourage you to access the Meeting online prior to the start time. The only item of information needed to access the Meeting from the website is the control number, which is the 15-digit number located in the shaded bar on the Notice of Internet Availability you receive or on the proxy card. Have the Notice of Internet Availability or proxy card available when you access the website and then follow the instructions. If you are a stockholder of record, you are already registered for the Meeting.

Beneficial Stockholders

If you are a beneficial stockholder, then you may not attend and vote at the Meeting unless you obtain a “legal proxy” from your bank, broker or other nominee and register to attend the Meeting. You must follow the process for obtaining a legal proxy set out by your bank, broker or other nominee and forward a copy of the legal proxy along with your email address to Computershare. Requests for registration should be directed to Computershare via email at [email protected] or by mail:

Computershare

Zymeworks Inc. Legal Proxy

P.O. Box 43001

Providence, RI 02940-3001

Registered Holders of Exchangeable Shares

If you are a registered holder of exchangeable shares, then you may not attend and exercise the voting rights of your exchangeable shares at the Meeting unless you obtain a “legal proxy” from the share trustee and register to attend the Meeting. You must follow the instructions in your voting instruction card to obtain the legal proxy and forward a copy of the legal proxy along with your email address to Computershare. Requests for registration should be directed to Computershare via email at [email protected] or by mail:

Computershare Trust Company of Canada

320 Bay Street, 14th Floor,

Toronto, Ontario, M5H 4A6

Canada

Beneficial Holders of Exchangeable Shares

If you are a beneficial holder of exchangeable shares, then you may not attend and exercise the voting rights of your exchangeable shares at the Meeting unless you follow the instructions provided by your bank, broker or other nominee and obtain a “legal proxy” to exercise voting rights. You must follow the process for obtaining a legal proxy set out by your bank, broker or other nominee and forward a copy of the legal proxy along with your email address to Computershare. Requests for registration should be directed to Computershare via email at [email protected] or by mail:

Computershare Trust Company of Canada

320 Bay Street, 14th Floor,

Toronto, Ontario, M5H 4A6

Canada

Why are you holding a virtual meeting instead of a physical meeting?

We are excited to embrace the latest technology to provide expanded access, improved communication and cost savings for our stockholders and the Company. We believe that hosting a virtual meeting will enable more of our stockholders to attend and participate in the Meeting since our stockholders can participate from any location around the world with Internet access.

6

What if I have trouble accessing the Meeting virtually?

The virtual meeting platform is fully supported across browsers (MS Edge, Firefox, Chrome and Safari) and devices (desktops, laptops, tablets and cell phones) running the most up-to-date version of applicable software and plugins. Note: Internet Explorer is not a supported browser. Participants should ensure that they have a strong WiFi connection wherever they intend to participate in the Meeting. We encourage you to access the Meeting prior to the start time. For further assistance should you need it you may call Local 1-888-724-2416 or International +1 781-575-2748.

How will my shares be voted?

Stockholders

If you are a registered stockholder and you submit a proxy, your shares will be voted as you instruct. If you submit a proxy but do not provide voting instructions, your shares will be voted:

In addition, if any other matters are properly brought before the Meeting, the persons named as proxies will be authorized to vote or otherwise act on those matters in accordance with their judgment.

If you are a beneficial stockholder, your shares will be voted as you instruct on the voting instruction card provided by your broker. If you do not return the voting instruction card on a timely basis, your broker will have the authority to vote your brokerage shares only on the proposal to ratify the appointment of our independent registered public accounting firm. Your broker will be prohibited from voting your shares without your instructions on the election of directors and on any other proposal. These “broker non-votes” will be counted only for the purpose of determining whether a quorum is present at the Meeting and not as votes cast.

Holders of Exchangeable Shares

If you are a registered holder of exchangeable shares, your voting rights will be exercised as you instruct in your voting instruction card. If you do not return your instruction card, or if you sign and return your voting instruction card but do not provide voting instructions, your voting rights will not be exercised, and your shares will not count towards quorum at the Meeting.

If you are a beneficial holder of exchangeable shares, your exchangeable shares will be voted as you instruct on the voting instruction card provided by your broker. If you do not return your voting instruction card on a timely basis, the voting rights in respect of your exchangeable shares will not be exercised. The share trustee will be prohibited from exercising the voting rights in respect of your exchangeable shares without your instructions on the election of directors and on any other proposal. Your votes will not be counted and will not count towards a quorum at the Meeting.

May I change or revoke my vote?

If you are a registered stockholder, you may change your vote by: (i) providing a written notice of revocation to our Corporate Secretary at the address set out under the heading “Proxy Materials—I share an address with another stockholder, and we received only one paper copy of the Notice of Internet Availability or proxy statement and annual report, as applicable. How may I obtain an additional copy of the Notice of Internet Availability or proxy statement and annual report, as applicable?” provided that such notice is received prior to

7

3:00 p.m. Eastern Time on December 29, 2025; (ii) by attending the Meeting virtually by visiting meetnow.global/MZKC5MK and voting; or (iii) by granting a subsequent proxy. To be effective, the subsequent proxy must be deposited before the time specified above under the heading “How You Can Vote—When is the deadline to vote?” for the deposit of proxies.

Voting at the Meeting will revoke your previous proxy.

If you are a registered holder of exchangeable shares, you may change your vote by submitting a written revocation of your previous instruction to the share trustee. The written revocation must be received by 2:00 p.m. Eastern Time on December 24, 2025.

For shares of common stock or exchangeable shares you hold as a beneficial owner, you may change your vote by following the instructions provided by your bank, broker or other nominee.

Obtaining Additional Information

How may I obtain financial and other information about Zymeworks Inc.?

Our consolidated financial statements are included in our 2024 Annual Report on Form 10-K. We filed our Annual Report on Form 10-K with the SEC, 100 F Street, N.E., Washington, D.C. 20549, and, in Canada, on SEDAR+. We also will furnish a copy of our 2024 Form 10-K (excluding exhibits, except those that are specifically requested) without charge to any stockholder who so requests by writing to our Corporate Secretary at the address above under the heading in “Proxy Materials—I share an address with another stockholder, and we received only one paper copy of the Notice of Internet Availability or proxy statement and annual report, as applicable. How may I obtain an additional copy of the Notice of Internet Availability or proxy statement and annual report, as applicable?”.

By writing to us, stockholders also may obtain, without charge, a copy of our certificate of incorporation, bylaws, corporate governance principles and guidelines, code of business conduct and ethics and Board of Directors standing committee charters.

If you have any questions or need assistance voting, please contact Kingsdale at 1-855-476-7981 (toll-free in North America) or 1-473-561-5034 (text or collect outside North America) or email [email protected].

What if I have questions for the transfer agent?

If you are a registered stockholder and have questions concerning stock certificates, ownership transfer or other matters relating to your account, please contact our transfer agent at the following address:

Computershare Trust Company, N.A.

150 Royall Street

Canton, MA 02021

or P.O. Box 43006

Providence, RI 02940-3006

United States or Canada: (800) 736-3001

Non-United States or Canada: (781) 575-3100

If you are a registered holder of exchangeable shares and have questions concerning share certificates, ownership transfer or other matters relating to your account, please contact our transfer agent at the following address:

Computershare Investor Services Inc.

320 Bay Street, 14th Floor,

Toronto, ON, M5H 4A6

8

SHARE OWNERSHIP

The table below indicates information as of November 3, 2025 regarding the beneficial ownership of our common stock for:

In accordance with SEC rules, for the purposes of calculating percent ownership, as of November 3, 2025, (i) 74,835,565 shares of common stock were issued and outstanding, and, (ii) for any individual who beneficially owned shares represented by exchangeable shares, warrants, options, or restricted stock units that were exercisable or scheduled to vest within sixty days of November 3, 2025, those shares were treated as if outstanding for that person, but not for any other person. Unless otherwise indicated in the footnotes to the table, and subject to community property laws where applicable, the following persons have sole voting and investment control with respect to the shares beneficially owned by them. To our knowledge, except as noted in the table below, no person or entity was the beneficial owner of more than 5% of the voting power of our common stock as of November 3, 2025.

Except as otherwise indicated, the address of each of the persons in this table is 108 Patriot Drive, Suite A, Middletown, Delaware 19709.

9

10

11

Board Leadership

Our Board of Directors has a Chair, currently Mr. Kenneth Galbraith, who has authority, among other things, to call and preside over the meetings of the Board of Directors. The Chair, in consultation with the chair of any applicable committee and other directors, as appropriate, shall establish the agenda for meetings of the Board of Directors. If the Chair is not an independent director, then a lead independent director should act as the effective independent leader of the Board of Directors and ensure the Board of Directors’ agenda will enable it to successfully carry out its duties.

Our corporate governance framework provides our Board of Directors flexibility to determine the appropriate leadership structure for our company, and whether the roles of Chair and Chief Executive Officer should be separated or combined. In making this determination, our Board of Directors considers many factors, including the needs of the business, our Board of Directors’ assessment of its leadership needs from time to time and the best interests of our stockholders. If the role of Chair is filled by a director who does not qualify as an independent director, then our corporate governance guidelines provide that one of our independent directors may serve as our lead independent director.

Mr. Galbraith has extensive knowledge of all aspects of our business and industry, and is best positioned to identify strategic priorities, lead critical discussions, and execute our business plans. We believe that Mr. Galbraith’s combined role of Chair and Chief Executive Officer enables strong leadership, creates clear accountability, and enhances our ability to communicate our message and strategy clearly and consistently to our stockholders. Moreover, we believe that the combined role is both counterbalanced and enhanced with effective oversight by our independent directors and a strong independent board committee system. As a result of our Board of Directors having a majority of independent directors and its related independent committees, our Board of Directors maintains effective oversight of our business operations, including independent oversight of our financial statements, executive compensation, selection of director candidates and corporate governance programs. Accordingly, we believe that our current leadership structure is appropriate and enhances the Board of Directors’ ability to effectively carry out its roles and responsibilities on behalf of our stockholders.

Because Mr. Galbraith is the Chair of our Board of Directors and also our Chief Executive Officer and President, our Board of Directors appointed Dr. Susan Mahony to serve as our lead independent director. As lead independent director, Dr. Mahony presides over periodic meetings of our independent directors, serves as a liaison between Mr. Galbraith and our independent directors, works with the other directors to ensure the Board of Directors is provided with timely and relevant information as is necessary to effectively discharge its fiduciary duties and responsibilities, ensures that the Board of Directors and its committees have the appropriate resources to support their work, in particular, accurate, timely and relevant information, and performs such additional duties as our Board of Directors may otherwise determine or delegate.

We have a separate chair for each committee of the Board of Directors. The chairs of each committee are expected to report regularly to the Board of Directors on the activities of their committee in fulfilling their responsibilities as detailed in their respective charters.

On November 3, 2025, Dr. Davidson, Dr. Gallagher, and Mr. Miller submitted their resignations from the Board of Directors, including each director’s committee memberships, effective as of November 6, 2025. The resignations of Dr. Davidson, Dr. Gallagher, and Mr. Miller were not the result of any disagreement with the Company on any matter relating to the Company’s operations, policies or practices.

Risk Oversight

Our Board of Directors is responsible for the general oversight of risks that affect us. Our Board of Directors receives regular reports on our operations from our Chief Executive Officer, as well as other members of management. Our Board of Directors reviews these reports and makes inquiries in their business judgment.

14

Our Board of Directors also fulfills its oversight role through the operations of its various committees, including our audit committee. Our Board of Directors receives periodic reports on each committee’s activities. Our audit committee has, among its delegated responsibilities, the duty to assist the Board of Directors in its oversight of our risk management processes across the organization (including general enterprise risk, financial risk, cybersecurity, and data privacy matters). Our audit committee also has responsibility for risk oversight in connection with its review of our financial reports filed with the SEC. Our audit committee receives reports from our Chief Financial Officer and our independent auditors in connection with the review of our quarterly and annual financial statements regarding significant financial transactions, accounting and reporting matters, critical accounting estimates and management’s exercise of judgment in accounting matters. When reporting on such matters, our independent auditors also provide their assessment of management’s report and conclusions.

Environmental, Social and Governance Oversight

While the full Board of Directors has ultimate responsibility for oversight of environmental, social and governance (“ESG”) matters, the nominating and corporate governance committee is responsible for directly reviewing and reporting findings and recommendations to the Board of Directors regarding our ESG strategy, initiatives, and policies, including in light of any feedback from our management or other stakeholders. The nominating and corporate governance committee also periodically reviews our policies and disclosures related to ESG. These responsibilities of the nominating and corporate governance committee are expressly set forth in the committee’s charter. Although not enumerated in their respective charters, other committees of the Board of Directors also regularly address ESG issues relevant to their respective oversight areas.

Director Independence

Under the Nasdaq listing rules, independent directors must comprise a majority of a listed company’s board of directors. In addition, the listing standards of Nasdaq require that, subject to specified exceptions, each member of a listed company’s audit, compensation, and nominating and corporate governance committees be independent. Under the Nasdaq listing rules, a director will only qualify as an “independent director” if, in the opinion of that company’s board of directors, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director.

Audit committee members must also satisfy the additional independence criteria set forth in Rule 10A-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the Nasdaq listing rules. Compensation committee members must also satisfy the additional independence criteria set forth in Rule 10C-1 under the Exchange Act.

The Board of Directors has determined that all directors, except Mr. Galbraith, meet the independence requirements under the Nasdaq listing standards, and qualify as “independent directors” under the Nasdaq listing standards. Mr. Galbraith is not considered independent by virtue of being our Chief Executive Officer and President. The Board of Directors also determined that Mr. Campoy, Mr. Ciongoli and Mr. Landry, who comprise our audit committee, and Mr. Landry, Dr. Mahony, and Mr. Nodelman, who comprise our compensation committee, each satisfy the independence standards for those committees established by applicable SEC rules and the Nasdaq listing standards, and Dr. Cesano, Mr. Ciongoli and Mr. Nodelman, who comprise our nominating and corporate governance committee, are independent. In making these determinations, the Board of Directors considered the current and prior relationships that each non-employee director and director nominee has with our company and all other facts and circumstances that our Board of Directors deemed relevant in determining their independence, including the beneficial ownership of our capital stock by each non-employee director and director nominee, and the transactions involving them, including those described in the section titled “Certain Relationships and Related Transactions.”

15

There are no family relationships among any of our directors, director nominees or executive officers. The following directors are directors of other reporting issuers as of November 3, 2025, as set out below:

Board and Committee Meetings; Executive Sessions

At regularly scheduled Board of Directors and committee meetings, directors review and discuss management reports regarding our performance, prospects, and plans, as well as significant opportunities and immediate issues facing us. At least once a year, our Board of Directors also reviews management’s long-term strategic and financial plans.

The Chair, in consultation with the chair of any applicable committee, the lead independent director and other directors, as appropriate, establishes the agenda for meetings of the Board of Directors. Committee agendas and schedules are set by or in consultation with the committee chair. Directors are encouraged to propose agenda items, and any director also may raise at any meeting subjects that are not on the agenda.

Information and other materials important to understanding the business to be conducted at Board of Directors and its committee meetings, to the extent available, are distributed in writing to the directors in advance of the meeting. Additional information may be presented at the meeting.

To encourage and enhance communication among non-employee directors, and as required under applicable Nasdaq listing rules, our corporate governance guidelines provide that the independent directors will meet in executive sessions without the non-independent directors or members of management on a periodic basis but not less than two times a year.

During our fiscal year ended December 31, 2024, our Board of Directors held five meetings (including regularly scheduled and special meetings), and each director attended at least 75% of the aggregate of (1) the total number of meetings of the Board of Directors held during the period for which he or she has been a director and (2) the total number of meetings held by all committees on which he or she served during the periods that he or she served.

The table below provides the attendance record for our directors at meetings of the Board of Directors held in 2024:

16

We do not have a formal policy regarding attendance by members of our Board of Directors at our annual meetings of stockholders. One out of eleven then-members of our Board of Directors attended our 2024 annual meeting of stockholders.

Board Committees

The following chart sets forth our Board of Directors’ standing committees and membership on these committees as of the date of this proxy statement. Our Board of Directors dissolved our research and development committee effective November 6, 2025:

17

Audit Committee

Our audit committee currently consists of Mr. Campoy, Mr. Ciongoli and Mr. Landry. Mr. Cox ceased serving on the audit committee in August 2025 in connection with his resignation from the Board of Directors, and Mr. Miller ceased serving on the audit committee effective November 6, 2025 in connection with his resignation from the Board of Directors. Mr. Campoy serves as the chair of our audit committee. Our Board of Directors has determined that each of Mr. Campoy and Mr. Landry is an “audit committee financial expert” as that term is defined in the rules and regulations established by the SEC, and possesses financial sophistication, as defined under the rules of the Nasdaq Global Select Market. The members of our audit committee are “independent” for audit committee purposes, as that term is defined in the rules of the SEC and the applicable Nasdaq rules, and have sufficient knowledge in financial and auditing matters to serve on the audit committee.

The education and experience of each member of the audit committee that is relevant to the performance of their responsibilities as a member of the audit committee is described below under “Proposal 1—Election of Directors.”

The principal purposes of our audit committee are to:

Our Board of Directors has established a written charter setting forth the purpose, composition, authority and responsibility of our audit committee, consistent with the rules of Nasdaq and the SEC, a current copy of which is available on our website at www.zymeworks.com. Our audit committee has access to all of our books, records, facilities and personnel and may request any information about us as it may deem appropriate. It also has the authority in its sole discretion and at our expense to retain and set the compensation of outside legal, accounting or other advisors as necessary to assist in the performance of its duties and responsibilities. Both our independent auditors and internal financial personnel regularly meet privately with the audit committee and have unrestricted access to this committee.

18

Our audit committee held four meetings during the year ended December 31, 2024. The table below provides the attendance record for audit committee members at audit committee meetings held in 2024:

Compensation Committee

Our compensation committee currently consists of Mr. Landry, Dr. Mahony, and Mr. Nodelman and is chaired by Dr. Mahony. Mr. Renton ceased serving on the compensation committee in December 2024 in connection with his resignation from the Board of Directors. Each of Dr. Davidson and Dr. Gallagher ceased serving on the compensation committee effective November 6, 2025 in connection with their resignations from the Board of Directors. Mr. Platshon served on the compensation committee from February to November 2025, and Mr. Landry and Mr. Nodelman were appointed to the compensation committee in November 2025.

The functions of this committee include, but are not limited to:

19

Additional discussion of the role and responsibilities of the compensation committee is set forth below under “Executive Compensation—Discussion of Executive Compensation Practices.”

Our Board of Directors has established a written charter setting forth the purpose, composition, authority and responsibility of our compensation committee consistent with the rules of the Nasdaq and the SEC, a current copy of which is available on our website at www.zymeworks.com.

Our Board of Directors has determined that each of the current members of our compensation committee is independent as defined by Nasdaq rules.

Our compensation committee held four meetings during the year ended December 31, 2024. The table below provides the attendance record for our compensation committee members at compensation committee meetings held in 2024:

Nominating and Corporate Governance Committee

Our nominating and corporate governance committee is currently comprised of Dr. Cesano, Mr Ciongoli and Mr. Nodelman. Dr. Hillan resigned as a director and as chair and a member of the nominating and corporate

20

governance committee in February 2024, and Mr. Miller was appointed chair at that time. Mr. Nodelman was appointed as a member in February 2025. Mr. Miller ceased serving as the chair and a member of the nominating and corporate governance committee effective November 6, 2025 in connection with his resignation from the Board of Directors. Mr. Campoy ceased serving on the nominating and corporate governance committee in November 2025, and Mr. Ciongoli was appointed as a member and chair of the nominating and corporate governance committee in November 2025.

The nominating and corporate governance committee’s purpose is to assist our Board of Directors in:

It is the responsibility of the nominating and corporate governance committee to regularly evaluate the overall effectiveness of our Board of Directors and our Chair and all board committees and their chairs.

Our Board of Directors has not adopted director term limits or other automatic mechanisms of board renewal. Rather than adopting formal term limits, mandatory age-related retirement policies and other mechanisms of board renewal, the nominating and corporate governance committee has developed a skills and competencies matrix for our Board of Directors as a whole and for individual directors.

The nominating and corporate governance committee may retain, at our expense, outside counsel or other advisors as necessary to assist in the performance of its duties and responsibilities.

Our Board of Directors has established a written charter setting forth the purpose, composition, authority and responsibility of our nominating and corporate governance committee, a current copy of which is available on our website at www.zymeworks.com.

Director Nominations

Our nominating and corporate governance committee identifies, selects and recommends to the Board of Directors individuals qualified to serve both on the Board of Directors and on committees of the Board of Directors, including persons suggested by stockholders and others, in accordance with our certificate of incorporation and bylaws. In identifying new candidates for our Board of Directors, the nominating and corporate governance committee considers what competencies and skills our Board of Directors as a whole should possess, assesses the competencies and skills of each existing and potential director, and considers the personality and other qualities of each existing and potential director, as these may ultimately determine the boardroom dynamic. All directors are required to possess fundamental qualities of intelligence, honesty, integrity, ethical behavior, fairness, and responsibility and be committed to representing the long-term interests of the stockholders. They must also have a genuine interest in Zymeworks and be able to devote sufficient time to discharge their duties and responsibilities effectively.

The nominating and corporate governance committee seeks to identify qualified candidates for nomination as directors and make recommendations to the Board of Directors. When identifying candidates to nominate for election to the Board of Directors, the primary objectives of the nominating and corporate governance committee are to ensure consideration of individuals who are highly qualified, based on their talents, experience, functional expertise and personal skills, character, and qualities, having regard to our current and future plans and

21

objectives, as well as anticipated industry and market developments. In accordance with our corporate governance guidelines, the nominating and corporate governance committee also believes that having a diverse Board of Directors can offer a breadth and depth of perspectives that enhance the Board of Directors’ performance. The nominating and corporate governance committee values diversity of abilities, experience, perspective, education, gender, background, race and national origin and, accordingly, recommendations concerning director nominees are based on these considerations, in addition to merit and past performance, expected contribution to the Board of Directors’ performance, and knowledge of the industry and sector in which we operate. Additionally, in evaluating and identifying potential nominees, the nominating and corporate governance committee evaluates skills which may complement those already serving, or provide additional expertise not already present on the Board of Directors.

In furtherance of our commitment to diversity, the nominating and corporate governance committee will balance these objectives with the need to identify and promote individuals who are reflective of diversity for nomination for election to the Board of Directors. Although we have not adopted specific targets, the nominating and corporate governance committee will consider the level of representation of women and other diverse candidates on the Board of Directors when making recommendations for nominees to the Board of Directors.

We have engaged Egon Zehnder International Inc. (“Egon”) for the purpose of identifying highly qualified director nominee candidates that also align with our philosophy on diversity. Prior to their initial appointment to the Board of Directors, each of the director nominees at this year’s Meeting were first identified to the nominating and corporate governance committee by Egon.

The nominating and corporate governance committee will consider for nomination qualified director candidates recommended by our stockholders in accordance with our certificate of incorporation and bylaws. Any stockholder who wishes to recommend a director candidate is directed to submit written notice of the nomination to our Corporate Secretary at our principal executive offices. For details on the requirements for the submission of such notice, see “Proposal 1—Election of Directors—Advance Notice Policy” in this proxy statement.

All written submissions received from our stockholders will be reviewed by the nominating and corporate governance committee at the next appropriate meeting. The nominating and corporate governance committee will evaluate any suggested director candidates received from our stockholders in the same manner as recommendations received from management, committee members or members of our Board of Directors.

Our Board of Directors has determined that each of the members of our nominating and corporate governance committee is independent as defined by the Nasdaq rules.

The nominating and corporate governance committee met four times during the year ended December 31, 2024. The table below provides the attendance record for nominating and corporate governance committee members at nominating and corporate governance committee meetings held in 2024:

22

Research and Development Committee

We previously maintained a research and development committee as a committee of the Board of Directors. Following a review of the structure of our Board of Directors and its committees, in November 2025 our Board of Directors determined to dissolve the research and development committee.

Our research and development committee held two meetings during the year ended December 31, 2024. The table below provides the attendance record for research and development committee members at research and development committee meetings held in 2024:

Corporate Sustainability Initiatives

At Zymeworks, we are driven by our mission to make a meaningful difference for people around the world who are impacted by difficult-to-treat cancers and other serious diseases. We believe that we have a unique ability to use our combined talents to achieve something bigger than ourselves. As such, we are driven by our social purpose and place high value on our contributions to society and the environment, along with putting governance and compliance at the heart of everything we do.

For information regarding our Board of Directors’ oversight of ESG matters, see “Governance—Board of Directors—Environmental, Social and Governance Oversight.”

We hope to lead the way for biotechnology companies of our size and stage of development.

We will continue to invest in our employees and culture, and anticipate reporting on other corporate sustainability initiatives in the future.

Communications with the Board of Directors

Stockholders and other interested parties may contact any member (or all members) of our Board of Directors (including, without limitation, the non-management directors as a group), any committee of our Board of Directors or the chair of any such committee. Written correspondence may be sent addressed to our Board of Directors, any committee or any individual director, c/o Corporate Secretary, Zymeworks Inc., 108 Patriot Drive, Suite A, Middletown, Delaware 19709.

Our Senior Vice President, Corporate Secretary and General Counsel, Chief Financial Officer or Legal Department, in consultation with appropriate directors as necessary, will review all incoming communications

23

and screen for communications that (1) are solicitations for products and services, (2) relate to matters of a personal nature not relevant for our stockholders to act on or for our Board of Directors to consider and (3) matters that are of a type that are improper or irrelevant to the functioning of our Board of Directors or our business, for example, mass mailings, job inquiries and business solicitations. If appropriate, our Senior Vice President, Corporate Secretary and General Counsel, Chief Financial Officer or Legal Department will route communications to the appropriate director(s) or, if none is specified, then to the lead independent director.

Our Senior Vice President, Corporate Secretary and General Counsel, Chief Financial Officer or Legal Department may decide in the exercise of his, her or its judgment whether a response to any communication is necessary and shall provide a report to the nominating and corporate governance committee of any communications received for which the Senior Vice President, Corporate Secretary and General Counsel, Chief Financial Officer or Legal Department has responded.

These policies and procedures do not apply to (a) communications to non-management directors from our officers or directors who are stockholders or (b) stockholder proposals submitted pursuant to Rule 14a-8 under the Exchange Act.

Any requests for investor relations materials should be made to our Investor Relations Department.

As part of our ongoing stockholder engagement, members of management (including the Chair of our Board of Directors) and our Investor Relations Department (i) make themselves available to, and meet regularly with, stockholders in individual meetings and at investor conferences and (ii) provide reports of feedback from shareholder interactions to our Board of Directors for consideration and discussion. In addition, upon request, the Company has made and will continue to make independent directors available to meet with stockholders from time to time. Stockholder feedback continues to be important to us, and we are committed to continue to engage with stockholders to understand their views.

At our 2024 annual meeting, our non-binding advisory vote on executive compensation (commonly referred to as a “say-on-pay” vote) received approximately 93% of the votes cast in support of the proposal (excluding broker non-votes and abstentions). We frequently engage in stockholder outreach and discuss a wide range of topics, including discussions regarding compensation-related matters. We take our say-on-pay vote results seriously and will continue to consider the feedback we receive from stockholders and use such feedback to inform the compensation committee’s deliberations and decisions with respect to our executive compensation practices.

24

PROPOSALS TO BE VOTED ON

Proposals 1, 2 and 3 are included in this proxy statement at the direction of our Board of Directors. Our Board of Directors unanimously recommends that you vote “FOR” all of the nominees in Proposal 1, “FOR” Proposal 2 and “FOR” Proposal 3.

25

PROPOSAL 1—ELECTION OF DIRECTORS

Nominees

The nominating and corporate governance committee has recommended, and our Board of Directors has nominated, the following three individuals for election as directors, all of whom are currently directors:

In making the nominations, both our nominating and corporate governance committee and our Board of Directors considered the nominees’ other obligations, experience, tenure, and attendance record. Also, in furtherance of our commitment to diversity, our nominating and corporate governance committee balances these objectives with the need to identify and promote individuals who are reflective of diversity for nomination for election to our Board of Directors. Our nominating and corporate governance committee considers the level of representation of women and other diverse candidates on the Board of Directors when making recommendations for nominees to the Board of Directors. At this time, we have not adopted any specific targets for recruiting and retaining qualified female directors but will continue to pursue our objectives through ongoing diversity initiatives with a view to continue identifying and fostering the development of a suitable pool of candidates for nomination or appointment to our Board of Directors.

Our Board of Directors determined that Mr. Campoy, Dr. Cesano, and Mr. Landry are independent under applicable SEC and exchange standards.

Biographical information regarding each director nominee and their qualifications to serve as a director are set forth below as of November 3, 2025. Unless otherwise indicated, each director has held their principal occupation or other positions with the same or predecessor organizations for at least the last five years.

Carlos Campoy

Mr. Campoy is 61 years old and has served as a member of our Board of Directors since June 2023. Mr. Campoy served as Chief Financial Officer of CytomX Therapeutics, Inc. from March 2020 through September 2022. Prior to CytomX Therapeutics, Mr. Campoy served as the Chief Financial Officer of Alder BioPharmaceuticals, Inc., a public biopharmaceutical company acquired in October 2019 by Lundbeck A/S, from December 2018 to November 2019. During his time at Alder BioPharmaceuticals, Mr. Campoy led the finance organization and readied the company for commercial launch of its lead program, eptinezumab. Prior to Alder BioPharmaceuticals, Mr. Campoy was a partner at Think Forwards, a boutique financial consulting firm, from September 2017 to December 2018. Prior to his position at Think Forwards, Mr. Campoy held the role of vice president of finance at Allergan plc from July 2014 to November 2016. Prior to joining Allergan, Mr. Campoy held senior financial leadership positions at Eli Lilly and Company from 1996 to 2014, including Chief Financial Officer of Eli Lilly Japan K.K. Mr. Campoy is NACD Directorship Certified^® and holds a Certified Management Accountant (CMA) designation. Mr. Campoy received his M.B.A. in Finance and Decision Information Systems from Indiana University and his B.S. in Management from Faculdade de Ciências Contábeis e de Administração de Empresas de Tupã (FACCAT), in São Paulo, Brazil.

The Board of Directors believes that Mr. Campoy is qualified to serve on our Board of Directors because of his extensive strategic and financial leadership experience in the pharmaceutical and biotechnology sectors.

Alessandra Cesano

Dr. Cesano is 65 years old and has served as a member of our Board of Directors since February 2024. Dr. Cesano has served as an advisor to General Catalyst, a venture capital and investment firm, since February

26

2025. Dr. Cesano served as the Chief Medical Officer of ESSA Pharma Inc., a pharmaceutical company developing therapies for the treatment of prostate cancer, from July 2019 to May 2025. Previously, Dr. Cesano was the Chief Medical Officer of NanoString Technologies, Inc., a biotechnology company that develops translational research tools, from July 2015 to July 2019, where she focused on development of translational and diagnostic multi-plexed assays for the characterization and measurement of mechanisms of immune response and resistance. Prior to NanoString, Dr. Cesano was Chief Medical Officer at Cleave Biosciences, Inc., a biopharmaceutical company focusing on protein therapies for the treatment of cancer and neurodegenerative diseases, and before that she served as Chief Medical Officer and Chief Operations Officer at Nodality, Inc., where she built and led the Research & Development group, while providing the overall clinical vision for the organization. Dr. Cesano has also held various management positions at Amgen Inc., Biogen Inc. (formerly Biogen Idec) and SmithKline Beecham Pharmaceuticals, where she helped to advance various oncology drugs through late-stage development and U.S. Food and Drug Administration (“FDA”) approvals. She currently serves as associate editor for the Biomarker section of the Journal for ImmunoTherapy of Cancer and co-chair of the Society for Immunotherapy of Cancer (SITC) regulatory committee. She has been an author on more than 140 publications. Dr. Cesano has served as a director at Puma Biotechnology, Inc. since July 2022 and as a director of Summit Therapeutics Inc. since November 2022. Dr. Cesano received an M.D. summa cum laude, a board certification in oncology and a Ph.D. in Tumor Immunology from the University of Turin, Italy.

The Board of Directors believes that Dr. Cesano is qualified to serve on our Board of Directors because of her extensive experience in biotechnology research and development and oncology.

Robert E. Landry

Mr. Landry is 61 years old and has served as a member of our Board of Directors since August 2025. Mr. Landry served as the Executive Vice President and Chief Financial Officer at Regeneron Pharmaceuticals, Inc., from September 2013 to January 2024. Prior to his time at Regeneron, Mr. Landry served from January 1988 to August 2013 as the Senior Vice President, Treasurer, Senior Vice President, Finance, and in other various corporate roles at Pfizer (formerly Wyeth). Mr. Landry started his career at Coopers & Lybrand, now PricewaterhouseCoopers LLP. Mr. Landry also currently serves on the board of directors of Cytokinetics, Inc., a late-stage biopharmaceutical company. Mr. Landry is a Certified Public Accountant in New York (inactive) and attended the University of Notre Dame, where he earned a B.B.A. in accounting in 1986.

The Board of Directors believes that Mr. Landry is qualified to serve on our Board of Directors because of his extensive financial and leadership experience, in addition to his knowledge of our industry.

THE BOARD OF DIRECTORS RECOMMENDS THAT YOU VOTE “FOR” THE ELECTION AS DIRECTORS OF THE THREE NOMINEES NAMED IN THIS PROXY STATEMENT.

Continuing Members of the Board of Directors

Biographical information regarding the members of the Board of Directors expected to continue in office following the conclusion of the Meeting is set forth below as of November 3, 2025. Unless otherwise indicated, each director has held their principal occupation or other positions with the same or predecessor organizations for at least the last five years.

Gregory A. Ciongoli

Mr. Ciongoli is 50 years old and has served as a member of our Board of Directors since August 2025. Mr. Ciongoli is currently the Founder and Managing partner at Adiumentum Capital Management, a Boston-based investment firm, and has served in that role since March 2024. Mr. Ciongoli has also served on the board of directors of Atara Biotherapeutics since September 2024, including as board chair since September 2025.

27

Mr. Ciongoli served as a Public Group Investing Partner at the Baupost Group from 2007 to 2024. Mr. Ciongoli has served on the board of directors of Pelotero Corp. since March 2020, 33^rd Team since September 2022, and Wavebreak Therapeutics since August 2017, and served as a board observer at Viasat Inc. from October 2018 to May 2023. In addition, Mr. Ciongoli previously served as a board observer at Idenix Pharmaceuticals, Intarcia Therapeutics, Keryx Biopharmaceuticals, Orexigen Therapeutics and Translate Bio. Earlier in his career, Mr. Ciongoli held the position of Director in the Event-Driven Equity Group at Sowood Capital Management from 2005 to 2007 and worked as an Investment Analyst at Vinik Asset Management from 2003 to 2005 and at Thomas H. Lee Partners from 1999 to 2001. Mr. Ciongoli began his career as a Financial Analyst in the Healthcare Investment Banking Group at Goldman, Sachs & Co. from 1997 to 1999. Mr. Ciongoli also serves as the Chair of the Advisory Board for the James Madison Program in American Ideals and Institutions at Princeton University, and is actively involved in a number of local not-for-profit organizations. Mr. Ciongoli earned a Master in Business Administration degree from Harvard Business School in June 2003 and earned his Bachelor of Arts degree from the Woodrow Wilson School of Public and International Affairs at Princeton University in 1997.

The Board of Directors believes that Mr. Ciongoli is qualified to serve on our Board of Directors because of his extensive strategic leadership experience in the pharmaceutical sector.

Kenneth Galbraith

Mr. Galbraith is 63 years old and has served as our Chief Executive Officer and Chair of our Board of Directors since January 2022. In addition, Mr. Galbraith has served as our President since June 2023 and previously served as our President from January 2022 to August 2022, and served as our interim Chief Financial Officer from April 2024 to September 2024. Mr. Galbraith was a Managing Director at Five Corners Capital, Inc., which he founded in 2013, from February 2021 until January 2022. He served as Executive in Residence at Syncona Investment Management Limited (“SIML”, a subsidiary of Syncona Limited, a company that builds a portfolio of life sciences businesses), from April 2021 until January 2022. He has served as an advisor to SIML since May 2023 and as a director of SIML since November 2024, including as Chair since February 2025. He served as Chief Executive Officer of Liminal BioSciences Inc. (formerly Prometic Life Sciences Inc.), a publicly held company, from April 2019 to November 2020, continuing as an advisor to that company from November 2020 to February 2021. He also served as Chief Executive Officer of Fairhaven Pharmaceuticals Inc. from June 2017 to April 2019. Mr. Galbraith has served as a director of several publicly held companies, including MacroGenics, Inc. from July 2008 until January 2022, Profound Medical Corp. from January 2017 to May 2023, and Celator Pharmaceuticals, Inc. from July 2008 to October 2013. He has also served as a director of several privately held companies. Previously, he joined Ventures West Capital in 2007 and founded Five Corners Capital Inc. in 2013 to manage the continued operations of the Ventures West Investment Funds. Mr. Galbraith has over 35 years of experience serving as an executive, director, investor and adviser to companies in the biotechnology, medical device, pharmaceutical and healthcare sectors. Mr. Galbraith received his B.Comm. from the University of British Columbia.

Based on Mr. Galbraith’s depth of experience in the biotechnology industry, ranging from executive officer to director roles, the Board of Directors believes Mr. Galbraith has the appropriate set of skills to serve as a member of our Board of Directors.

Susan Mahony

Dr. Mahony is 61 years old and has served as a member of our Board of Directors since June 2019 and as Lead Independent Director of our Board of Directors since December 2023. Dr. Mahony is an executive with over 30 years of experience in pharmaceutical and life sciences companies. Dr. Mahony served as Senior Vice President of Eli Lilly and Company and President of Lilly Oncology from February 2011 until August 2018. She joined Lilly in 2000, holding senior leadership positions in product development, marketing, human resources, and general management. Prior to joining Lilly, Dr. Mahony served in sales and marketing roles in Europe for over a

28

decade for Schering-Plough, Amgen, and Bristol-Myers Squibb. Dr. Mahony has served on the board of directors of Assembly Biosciences, Inc. since December 2017, on the board of directors of Axsome Therapeutics, Inc. since October 2023, and on the board of directors of Catalent, Inc. since February 2025. She previously served on the board of directors of Horizon Therapeutics Public Limited Company from August 2019 to October 2023 (acquired by Amgen Inc.) and on the board of directors of Vifor Pharma from May 2019 until August 2022 (acquired by CSL Limited). Dr. Mahony received a B.Sc. and a Ph.D. from Aston University and an M.B.A. from London Business School. Dr. Mahony is NACD Directorship Certified^®.

Based on Dr. Mahony’s extensive experience in management at public pharmaceutical companies, together with her experience serving on the board of directors of public and private companies, our Board of Directors concluded that she should serve as a director due to our business focus and strategy.

Kelvin Neu

Dr. Neu is 51 years old and has served as a member of our Board of Directors since March 2020. Dr. Neu is Founder and Chief of Herringbone, a life sciences innovation practice established in February 2022. Dr. Neu is also Co-Founder and Director of QDX Pte Ltd and QDX Technologies Pte Ltd (which work in the area of computational drug discovery) and XBI Biosciences LLC (a therapeutics development company). Previously, Dr. Neu was a Partner at Baker Bros. Advisors LP, a registered investment adviser, where he worked from 2004 until 2021. Dr. Neu previously served on the board of directors of IGM Biosciences from 2019 to 2021, Prelude Therapeutics from 2016 to 2021, Idera Pharmaceuticals, Aquinox Pharmaceuticals and XOMA Corporation. Dr. Neu holds an M.D. from the Harvard Medical School-MIT Health Sciences and Technology program, and spent three years in the Immunology Ph.D. program at Stanford University as a Howard Hughes Medical Institute Fellow. Dr. Neu holds an A.B. (summa cum laude) from Princeton University, where he was awarded the Khoury Prize for graduating first in his department of Molecular Biology.

The Board of Directors believes that Dr. Neu is qualified to serve on our Board of Directors because of his extensive investment and leadership experience, knowledge of our industry, and educational background in biology and biotechnology.

Oleg Nodelman

Mr. Nodelman is 48 years old and has served as a member of our Board of Directors since February 2025. Since October 2013, Mr. Nodelman has served as the Founder and Portfolio Manager of EcoR1 Capital LLC, a biotech-focused investment advisory firm established in 2013, and one of our principal stockholders. Previously, Mr. Nodelman served as a Portfolio Manager at BVF Partners from 2001 to 2012. Mr. Nodelman earned a B.S.F.S. in Science and Technology from Georgetown University, School of Foreign Service in 1999. Mr. Nodelman has served on the board of Galapagos NV since October 2024 and AnaptysBio since April 2021. He previously served on the board of directors of Prothena Corporation plc from December 2019 to December 2024, Nuvation Bio Inc. from February 2021 to December 2023 and Panacea Acquisition Corp. II from April 2020 to February 2021. On December 13, 2024, the Enforcement Committee of the Autorité des Marchés Financiers (“AMF”), the entity that regulates the French financial markets, fined Mr. Nodelman and EcoR1 Capital LLC (the “Fund”) €3.0 million and €7.0 million, respectively, for violations of applicable market abuse regulations and failures to comply with reporting obligations for holders that exceed or fall below ownership of five percent of an issuer’s equity capital that is listed on Euronext Paris. Mr. Nodelman and the Fund disagree with the AMF’s ruling and, in February 2025, submitted an appeal, which they intend to vigorously pursue.

The Board of Directors believes that Mr. Nodelman is qualified to serve on our Board of Directors because of his extensive investment and leadership experience, in addition to his knowledge of our industry.

Scott Platshon

Mr. Platshon is 34 years old and has served as a member of our Board of Directors since February 2024. Mr. Platshon has served as a Partner at EcoR1 Capital since December 2020. Mr. Platshon was also a Principal at

29

EcoR1 Capital from December 2017 to December 2020, and has been with EcoR1 Capital since October 2015. Prior to joining EcoR1 Capital, Mr. Platshon served as an analyst at Aquilo Partners, a San Francisco life-sciences investment bank, from September 2014 to September 2015. Mr. Platshon has served on the board of directors of Kumquat Biosciences Inc. since February 2021 (prior to that he was a board observer since August 2019) and Ajax Therapeutics, Inc. since May 2021, and previously served on the board of directors of Terremoto Biosciences from October 2023 to December 2024. Mr. Platshon received his B.S. in Bioengineering from Stanford University. As previously disclosed, pursuant to the securities purchase agreement with certain institutional accredited investors affiliated with EcoR1 Capital, LLC (collectively, “EcoR1”), we agreed that EcoR1 would have the right to nominate one of its partners as a member of our Board of Directors, with such nomination right terminating upon the earliest of the effective date of such appointment and January 1, 2026. Pursuant to this nomination right, Mr. Platshon was designated by EcoR1 as its nominee for the Board of Directors’ consideration for appointment to the Board of Directors and was appointed to the Board of Directors on February 22, 2024.

The Board of Directors believes that Mr. Platshon is qualified to serve on our Board of Directors because of his extensive investment and leadership experience, in addition to his knowledge of our industry.

Staggered Board Provisions

Our certificate of incorporation provides for a staggered board of directors consisting of three groups of directors, with directors serving staggered three-year terms. We are committed to strong corporate governance, and our Board of Directors believes that our staggered board structure provides important benefits to us and our stockholders, including promotion of our long-term objectives, enhanced director independence, stability and continuity of leadership, and protection from unsolicited takeovers. In addition, many of our peer companies at a similar stage of development employ a similar staggered board structure.

Each director’s term continues until the expiration of the term for which such director was elected and until such director’s successor is elected and qualified or until such director’s earlier death, resignation or removal. Upon the resignation of a director, the remaining directors may fill the vacancy resulting from the resignation for the remainder of the unexpired term.

Our directors or director nominees are up for re-election or election, respectively, as follows:

Replacement or Removal of Directors

Directors appointed to fill vacancies shall hold office until the remainder of the unexpired portion of the term of the departed director that was replaced.

Under our certificate of incorporation and bylaws, the number of directors of Zymeworks is set by our Board of Directors from time to time, except that the Board of Directors may not increase the number of directorships by more than 1/3 of the number of directors in office at the conclusion of the most recent annual meeting of stockholders prior to the next annual meeting of stockholders. Our Board of Directors has set the number of directors at nine.

30

Majority Voting Policy

We have adopted a “majority voting policy” to the effect that a nominee for election as a director of Zymeworks who does not receive a greater number of votes “for” than votes “withheld” with respect to the election of directors by stockholders must offer to tender their resignation to the Chair of our Board of Directors promptly following the meeting of stockholders at which the director was elected. The nominating and corporate governance committee will consider such offer and make a recommendation to our Board of Directors whether or not to accept such resignation. Our Board of Directors will promptly accept the resignation unless it determines, in consultation with the nominating and corporate governance committee, that there are exceptional circumstances relating to the composition of the Board of Directors or the voting results that should delay the acceptance of the resignation or justify rejecting it. Our Board of Directors will make its decision and announce it in a press release within 90 days following the meeting of stockholders. A director who tenders a resignation pursuant to our majority voting policy will not participate in any meeting of our Board of Directors or the nominating and corporate governance committee at which the resignation is considered. Our majority voting policy does not apply to contested meetings at which the number of directors nominated for election is greater than the number of seats available on the Board of Directors.

Advance Notice Policy

If a stockholder would like us to consider including a proposal in our proxy statement pursuant to Rule 14a-8 of the Exchange Act, then the proposal must be received by our Corporate Secretary at our principal executive offices on or before 120 calendar days before the first anniversary of the date our proxy statement was released to shareholders in connection with the previous year’s annual meeting. In addition, stockholder proposals must comply with the requirements of Rule 14a-8 regarding the inclusion of stockholder proposals in company-sponsored proxy materials. Proposals should be addressed to:

Zymeworks Inc.

Attention: Corporate Secretary

108 Patriot Drive, Suite A

Middletown, Delaware 19709

Our amended and restated bylaws also establish an advance notice procedure for stockholders who wish to nominate a director, or present a proposal without seeking to include it in our proxy statement. In order to be properly brought before an annual meeting, the stockholder must provide timely written notice to our Corporate Secretary, at our principal executive offices, and any such proposal or nomination must constitute a proper matter for stockholder action. The written notice must contain the information specified in our amended and restated bylaws. To be timely, a stockholder’s written notice must be received by our Corporate Secretary at our principal executive offices no earlier than 8:00 a.m., Eastern Time, on the 120th day and no later than 5:00 p.m., Eastern Time, on the 90th day prior to the day of the first anniversary of the preceding year’s annual meeting as first specified in our notice of such annual meeting (without regard to any adjournment, rescheduling, postponement or other delay of such annual meeting occurring after such notice was first sent).

In the event that we hold our 2026 annual meeting more than 25 days before or after the one-year anniversary of this year’s annual meeting, then such written notice must be received by our Corporate Secretary at our principal executive offices no earlier than 8:00 a.m., Eastern Time, on the 120th day prior to the day of such annual meeting and no later than 5:00 p.m., Eastern Time, on the later of (i) the 90th day prior to the day of the annual meeting or, (ii) if the first public announcement of the date of such annual meeting is less than 100 days prior to the date of such annual meeting, the 10th day following the day on which public announcement of the date of the annual meeting was first made by us.

If a stockholder who has notified us of his, her or its intention to present a proposal at an annual meeting of stockholders does not appear to present his, her or its proposal at such annual meeting, then we are not required to present the proposal for a vote at such annual meeting.

31

Certain Relationships and Related Transactions

Other than as discussed below and the compensation arrangements discussed under “Executive Compensation Discussion of Executive Compensation Practices,” since January 1, 2023, there have not been any transactions to which we are a party, nor are there any proposed transactions to which we would be a party, with related parties and which we are required to disclose pursuant to the rules of the SEC.

On June 16, 2023, EcoR1 purchased an aggregate of 3,350,000 shares of common stock at $8.12 per share under our at-the-market sales agreement, dated as of November 9, 2022, with Cantor Fitzgerald & Co. We received gross proceeds of $27.2 million and net cash proceeds of $26.2 million, after underwriting commissions and offering expenses. EcoR1 beneficially owned more than 5% of our shares of common stock prior to this purchase.

On December 28, 2023, EcoR1 purchased an aggregate of 5,086,521 pre-funded warrants to purchase 5,086,521 shares of our common stock in a private placement. The per share purchase price for the pre-funded warrants was $9.8299, for an aggregate purchase price of approximately $50 million. In connection with the private placement, we entered into a registration rights agreement with EcoR1 requiring us to register the resale of the shares of our common stock issuable upon exercise of the pre-funded warrants. In addition, we agreed that EcoR1 would have the right to nominate one of its partners as a member of our Board of Directors, subject to specified conditions. On February 22, 2024, our Board of Directors appointed Mr. Scott Platshon as a member of our Board of Directors. EcoR1 beneficially owned more than 5% of our shares of common stock prior to this purchase. Under the registration rights agreement, we agreed to file a registration statement covering the resale by EcoR1 of their registrable securities upon the earlier of March 15, 2024 and the first business day following the date that we file our Annual Report on Form 10-K for the fiscal year ended December 31, 2023. We agreed to use commercially reasonable efforts to cause such registration statement or final prospectus, as applicable, to be declared effective as soon as practicable, but no later than the later of April 29, 2024 and the 123rd calendar day following the closing date, and to keep such registration statement effective for a period that will terminate upon the earliest of (i) the date that all registrable securities covered by such registration statement or final prospectus, as applicable, have been sold, (ii) the date that all registrable securities covered by such registration statement or final prospectus, as applicable, may be sold without the requirement for us to be in compliance with the current public information required under Rule 144 as to such registrable securities and without volume or manner-of-sale restrictions and (iii) two (2) years after the date of the securities purchase agreement. The registration statement filed pursuant to the registration rights agreement became automatically effective upon filing on March 7, 2024.

On June 26, 2025, we entered into an amendment to the outstanding pre-funded warrants issued to EcoR1 on December 28, 2023. Oleg Nodelman, the manager of EcoR1 Capital LLC, and Scott Platshon, a partner at EcoR1 Capital LLC are now and were at the time of the amendment members of our Board of Directors. The amendment removed the limitation on exercise contained in Section 12 of the pre-funded warrants, which prohibited the exercise of the pre-funded warrants if, after giving effect or immediately prior to such exercise, a purchaser, together with its affiliates and any other persons whose beneficial ownership of shares of our common stock would be aggregated with such purchaser for purposes of Section 13(d) of the Exchange Act would beneficially own more than 19.99% of the total number of issued and outstanding shares of our common stock or voting power following such exercise. On June 26, 2025, EcoR1 net exercised the pre-funded warrants in full to acquire 5,086,521 shares of our common stock at an exercise price of $0.0001 per share. We issued the shares pursuant to the exercise on June 27, 2025.

On August 10, 2025, we entered into a stock purchase agreement for a private placement with Mr. Ciongoli following his appointment as a director. Pursuant to the stock purchase agreement, Mr. Ciongoli agreed to purchase 415,000 shares of our common stock for an aggregate purchase price of $4,988,300. The per share purchase price of $12.02 represented the consolidated closing bid price of a share of our common stock on the Nasdaq on August 8, 2025. There were no underwriting discounts or commissions associated with the private placement. The private placement closed on August 12, 2025.

32

Each of these transactions was approved pursuant to our formal, written policy regarding related person transactions.

Indebtedness of Directors, Executive Officers and Employees

None of our directors, executive officers, employees, former directors, former executive officers or former employees, and none of their associates, is indebted to us or another entity whose indebtedness is the subject of a guarantee, support agreement, letter of credit or other similar agreement or understanding provided by us.

Policy Regarding Related Party Transactions

We have adopted a formal, written policy regarding related person transactions. This written policy regarding related person transactions provides that a related person transaction is a transaction, arrangement or relationship (or any series of similar transactions, arrangements or relationships), in which we are a participant and in which a related person has, had or will have a direct or indirect material interest and in which the aggregate amount involved exceeds $120,000. For purposes of this policy, a related person means any of our executive officers and directors (including director nominees), in each case at any time since the beginning of our last fiscal year, or holders of more than 5% of any class of our voting securities and any member of the immediate family of, or person sharing the household with, any of the foregoing persons.

Our audit committee has the primary responsibility for reviewing and approving, ratifying or disapproving related person transactions. In determining whether to approve, ratify or disapprove any such transaction, our audit committee will consider, among other factors, (1) whether the transaction is fair to us and on terms no less favorable than terms generally available to unaffiliated third parties under the same or similar circumstances, (2) the extent of the related person’s interest in the transaction, (3) whether there are business reasons for us to enter into such transaction, (4) whether the transaction would impair the independence of any of our outside directors and (5) whether the transaction would present an improper conflict of interest for any of our directors or executive officers.

The policy grants standing pre-approval of certain transactions, including (1) certain compensation arrangements for our directors or executive officers, (2) transactions with another company, other than an acquisition by us of that company, at which a related person’s only relationship is as a non-executive employee, director or beneficial owner of less than 10% of that company’s shares, provided that the aggregate amount involved does not exceed the greater of $1,000,000 or 2% of such company’s total annual revenues and the transaction is on terms no less favorable than terms generally available to unaffiliated third parties under the same or similar circumstances, (3) charitable contributions by us to a charitable organization, foundation or university at which a related person’s only relationship is as a non-executive employee or director, provided that the aggregate amount involved does not exceed the greater of $1,000,000 or 2% of such organization’s total annual receipts, (4) transactions where a related person’s interest arises solely from the ownership of our common stock and all holders of our common stock received the same benefit on a pro rata basis and (5) any indemnification or advancement of expenses made pursuant to our organizational documents or any agreement. In addition to our policy, our audit committee charter provides that our audit committee shall review and approve or disapprove any related person transactions.

Interests of Management and Others in Material Transactions

Other than as described elsewhere in this proxy statement, there are no material interests, direct or indirect, of any of our directors or executive officers, any stockholder that beneficially owns, or controls or directs (directly or indirectly), more than 5% of any class or series of our outstanding voting securities, or any associate or affiliate of any of the foregoing persons, in any transaction since January 1, 2023 that has materially affected or is reasonably expected to materially affect us or our subsidiaries.

33

PROPOSAL 2—ADVISORY VOTE ON THE COMPENSATION OF OUR NAMED EXECUTIVE OFFICERS

Pursuant to Section 14A of the Exchange Act, we are providing our stockholders with the opportunity to cast a non-binding, advisory vote regarding the compensation of our named executive officers as disclosed in this proxy statement. This proposal, commonly known as a “say-on-pay” proposal, gives our stockholders the opportunity to endorse or not endorse our executive pay program and policies through the following resolution:

“RESOLVED, that the compensation paid to the Company’s named executive officers, as disclosed pursuant to the compensation disclosure rules of the Securities and Exchange Commission, including the Discussion of Executive Compensation Practices, compensation tables and related narrative discussion contained in the 2025 proxy statement, is hereby approved.”

As described in the section titled “Executive Compensation—Discussion of Executive Compensation Practices” included in this proxy statement below, we believe that our executive compensation program is designed to support our long-term success.

We urge stockholders to read the section titled “Executive Compensation—Discussion of Executive Compensation Practices” and the related narrative and tabular compensation disclosure included in this proxy statement. The “Discussion of Executive Compensation Practices” provides detailed information regarding our executive compensation program and policies and procedures, as well as the compensation of our named executive officers.

Required Vote: Adoption of a non-binding, advisory resolution approving the compensation of our named executive officers as disclosed in this proxy statement requires the affirmative vote of a majority of the votes cast. Broker non-votes and abstentions will be considered for purposes of establishing a quorum at the Meeting but will not be considered as votes cast for or against a proposal. While this non-binding, advisory vote on the compensation of our named executive officers is not binding on us, our Board of Directors or the compensation committee, we value the opinions of our stockholders. Accordingly, our Board of Directors and the compensation committee will consider the outcome of this non-binding, advisory vote when making future compensation decisions for our named executive officers. Currently, we conduct non-binding, advisory votes on the compensation of our named executive officers on an annual basis, and the next non-binding, advisory vote on the compensation of our named executive officers will be held at our 2026 annual meeting of stockholders.

THE BOARD OF DIRECTORS RECOMMENDS THAT YOU VOTE “FOR” THE APPROVAL, ON A NON-BINDING, ADVISORY BASIS, OF THE COMPENSATION PAID TO THE COMPANY’S NAMED EXECUTIVE OFFICERS.

34

PROPOSAL 3—RATIFICATION OF APPOINTMENT OF AUDITORS

The members of our audit committee and our Board of Directors believe the continued retention of KPMG as our independent registered accounting firm is in our best interests and the best interests of our stockholders. Ratification requires the affirmative vote of a majority of the votes cast for or against the proposal. Broker non-votes and abstentions will be considered for purposes of establishing a quorum at the Meeting but will not be considered as votes cast for or against a proposal. Representatives of KPMG are not expected to attend the Meeting, but have been given an opportunity to make a statement if they so desire.

Principal Independent Accountant Fees and Services

KPMG has served as our independent registered public accounting firm since June 24, 2015. Aggregate fees billed by our independent auditors, KPMG, for the years ended December 31, 2024 and December 31, 2023, are detailed in the table below:

Pre-approval Policies and Procedures

Our audit committee has established a policy of reviewing, in advance, and either approving or not approving, all audit, audit-related, tax and other non-audit services that our independent registered public accounting firm provides to us. This policy requires that all services received from independent registered public accounting firms be approved in advance by the audit committee or a delegate of the audit committee. The audit committee has delegated pre-approval responsibility to the chair of the audit committee with respect to audit and permissible non-audit services and any associated fees. All services that KPMG provided to us in 2024 and 2023 have been pre-approved by our audit committee.

Our audit committee has determined that the provision of the services as set out above is compatible with the maintaining of KPMG’s independence in the conduct of their auditing functions.

THE BOARD OF DIRECTORS RECOMMENDS THAT YOU VOTE “FOR” THE RATIFICATION OF THE APPOINTMENT OF KPMG AS THE COMPANY’S INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM.

35

Audit Committee Report

The material in this report is not “soliciting material,” is not deemed “filed” with the SEC, and is not to be incorporated by reference into any filing by Zymeworks under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act.

The primary purpose of the audit committee is to oversee the Company’s financial reporting processes on behalf of the Board of Directors. Management has the primary responsibility for the Company’s financial statements and reporting processes, including the Company’s systems of internal controls. In fulfilling its oversight responsibilities, the audit committee reviewed and discussed with management Zymeworks’ audited financial statements and the effectiveness of the Company’s internal control over financial reporting as of and for the year ended December 31, 2024.

The audit committee has discussed with KPMG LLP, the Company’s independent registered public accounting firm, the matters required to be discussed under applicable requirements of the Public Company Accounting Oversight Board (“PCAOB”) and the SEC. In addition, the audit committee discussed with KPMG LLP its independence, and received from KPMG LLP the written disclosures and the letter required by applicable requirements of the PCAOB. Finally, the audit committee discussed with KPMG LLP, with and without management present, the scope and results of KPMG LLP’s audit of such financial statements.

Based on these reviews and discussions, the audit committee recommended to the Board of Directors that such audited financial statements be included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, as filed with the SEC on March 5, 2025.

Audit Committee of the Board of Directors

Carlos Campoy (Chair)

36

EXECUTIVE OFFICERS

The following table sets forth the names, ages and positions of our executive officers as of November 3, 2025:

There are no family relationships among any of the directors or executive officers.

The following is biographical information for our executive officers as of November 3, 2025, other than Mr. Galbraith, whose biographical information is included above.

Leone Patterson

Ms. Patterson joined Zymeworks in September 2024 and serves as our Executive Vice President, Chief Business Officer and Chief Financial Officer. Ms. Patterson served as Chief Financial Officer and Business Officer of Tenaya Therapeutics, Inc. from June 2021 until August 2024. Prior to joining Tenaya Therapeutics, Inc., Ms. Patterson joined Adverum Biotechnologies, Inc., a public clinical-stage gene therapy company, in June 2016 as the Chief Financial Officer and also served as Chief Executive Officer from May 2018 to June 2020, director from October 2018 to June 2020, and President from July 2020 to June 2021. Ms. Patterson has held various senior positions at Diadexus, Inc., Transcept Pharmaceuticals, Inc., NetApp, Inc., Exelixis, Inc., Novartis AG, Chiron (acquired by Novartis AG), and KPMG. Ms. Patterson has served on the board of directors and as the chair of the audit committee of Nkarta, Inc., a publicly traded biotechnology company, since April 2020. In addition, Ms. Patterson has served on the board of directors and as the chair of the audit committee of Kalaris Therapeutics Inc., a publicly traded biotechnology company, since April 2025. She previously served as a member of the board of directors of Eliem Therapeutics, Inc. from March 2021 to December 2024 and Adverum Biotechnologies, Inc. from October 2018 to June 2020, both publicly traded biotechnology companies, and as a member of the board of directors of Oxford Biomedica (UK) Limited, a publicly traded contract development and manufacturing organization focused on cell and gene therapy, from March 2023 to December 2024. Ms. Patterson holds a B.S. in Business Administration and Accounting from Chapman University and an Executive M.B.A. from St. Mary’s College. Ms. Patterson is also a Certified Public Accountant (inactive status).

Paul A. Moore

Dr. Moore joined Zymeworks in July 2022 and serves as our Chief Scientific Officer. Dr. Moore has more than 25 years of U.S.-based experience in biologics drug discovery and development in biotechnology research. His career efforts have led to the discovery and development of a range of FDA-approved and clinical-stage biologics for patients with difficult-to-treat cancers and autoimmune conditions. Prior to joining Zymeworks, Dr. Moore served as Vice President, Cell Biology, and Immunology at MacroGenics from April 2008 to July 2022, leading a team of approximately 50 researchers engaged in the discovery, preclinical validation and clinical development of antibody-based therapeutics, including bispecific antibodies and antibody drug conjugates. Among the portfolio supported by Dr. Moore were FDA-approved Margenza (margetuximab-cmkb) for treatment of HER2+ breast cancer, Zynyz (retifanlimab-dlwr) for treatment of Merkel cell carcinoma and Tzield (teplizumab-mzwv) to delay onset of type I diabetes. Prior to joining MacroGenics, Dr. Moore was Director of Cell Biology at Celera from May 2005 to April 2008, where he oversaw research leveraging proteomic-based discoveries to validate

37

novel cancer targets suitable for antibody-based therapeutics. Dr. Moore began his industrial career at Human Genome Sciences (HGS), holding several titles within research culminating in Director of Lead Product Development, where he managed various genomic-based target discovery programs including efforts that led to the discovery, development, approval, and commercialization of Benlysta (belimumab) for the treatment of systemic lupus erythematosus. Dr. Moore has an extensive research record co-authoring over 75 peer-reviewed manuscripts and is a named co-inventor on over 50 issued U.S. patents. Dr. Moore holds a Ph.D. in Molecular Genetics from the University of Glasgow, performed post-doctoral work at the Roche Institute of Molecular Biology in Nutley, New Jersey, and also holds a degree in Biotechnology from the University of Strathclyde.

Jeffrey Smith

Dr. Smith joined Zymeworks in January 2023 as Senior Vice President, Early Stage Development and was promoted to Executive Vice President and Chief Medical Officer in January 2024. He is based at our European hub in Dublin, Ireland. Dr. Smith has held many senior positions within the pharmaceutical industry. Previously, Dr. Smith served as the Managing Director of Alder Biopharmaceuticals Inc. in Dublin, Ireland from March 2017 to October 2019, and as Senior Vice President, Translational Medicine at Alder Biopharmaceuticals Inc. in Seattle, U.S. from 2012 to March 2017. Dr. Smith was responsible for the clinical development (phase I - III) of eptinezumab (anti-CGRP antibody for migraine) and clazakizumab (anti-IL-6 antibody for rheumatoid arthritis and cancer cachexia). Dr. Smith was also a founder of Alder Biopharmaceuticals Inc. (founded 2004). Dr. Smith received his M.B. B.S. and M.D. from the University of London, UK and is a Fellow of the Royal College of Physicians in London.

Although we have not adopted specific targets for women and other diverse candidates in executive positions, the Board of Directors has always considered diversity as an important aspect of its decision making when recommending appointments for individuals to serve as executive officers.

38

EXECUTIVE COMPENSATION

Discussion of Executive Compensation Practices

This section describes our executive compensation philosophy and how we implemented it through our 2024 compensation program for our named executive officers. The named executive officers for 2024 are:

This discussion contains forward-looking statements that are based on our current plans, considerations, expectations and projections regarding future compensation programs. Actual compensation programs adopted in the future may differ materially from the various planned programs summarized in this discussion.

In the paragraphs that follow, we provide an overview and analysis of our compensation program and policies, the material compensation decisions we have made under those programs and policies, and the material factors that we considered in making those decisions.

Overview

Zymeworks is a clinical-stage biotechnology company developing a diverse pipeline of novel, multifunctional biotherapeutics to improve the standard of care for difficult-to-treat diseases. Zymeworks’ complementary therapeutic platforms and fully integrated drug development engine provide the flexibility and compatibility to precisely engineer and develop highly differentiated antibody-based therapeutic candidates.

2024 Financial Highlights

2024 Preclinical and Clinical Development Highlights

Corporate Milestones in 2024

2024 Advisory Vote on Executive Compensation

At our 2024 annual general meeting, we conducted an advisory vote on named executive officer compensation. At that meeting, 93.33% of the votes cast on the advisory vote proposal were supportive of our named executive

39

officer compensation program as disclosed in our 2024 proxy statement. Our next advisory vote on named executive officer compensation will be held at our 2025 annual general meeting.

The compensation committee reviewed the advisory vote results in the context of our overall compensation philosophy and programs, and based on the level of support, determined that no significant changes to our compensation policies and programs were necessary. The compensation committee will continue to consider the results from future stockholder advisory votes on named executive officer compensation and other relevant market developments affecting named executive officer compensation in order to determine whether any subsequent changes to our named executive officer compensation programs and policies would be warranted to reflect any stockholder concerns reflected in those advisory votes or to address market developments. We frequently engage in stockholder outreach and discuss a wide range of topics, including discussions regarding compensation-related matters. We take our say-on-pay vote results seriously and will continue to consider the feedback we receive from stockholders and use such feedback to inform the compensation committee’s deliberations and decisions with respect to our executive compensation practices.

Overview of Compensation Program

Compensation Philosophy

The goal of our compensation program is to attract, retain and motivate our employees and executives, including our named executive officers. The compensation committee is responsible for setting our executive compensation and reviewing and approving, or recommending to the Board of Directors for approval, the Company’s annual corporate performance objectives applicable to executive and other Company bonus programs. In considering executive compensation, the compensation committee strives to ensure that our total compensation is competitive within the industry in which we operate and supports our overall strategy and corporate objectives. The combination of base salary, annual incentives and long-term incentives that we provide our executives is designed to accomplish this.

Compensation Objectives

The objectives of our executive compensation program are to:

Role of the Compensation Committee

During 2024, the compensation committee’s work included the following:

40

In reaching its decisions, the compensation committee may consider input from management and other factors that the compensation committee considers appropriate. Decisions made by the compensation committee are the responsibility of the compensation committee and may reflect factors and considerations other than the information and/or recommendations provided by management.

Independent Compensation Consultant

In 2024, the compensation committee retained the Human Capital Solutions practice at Aon plc (“Aon”), as an independent consultant to the compensation committee to conduct competitive reviews and assessments of Zymeworks’ executive compensation program and recommend go-forward strategies. The compensation committee made the decision to retain Aon in its sole discretion and was directly responsible for the appointment, compensation and oversight of Aon’s work. The compensation committee is involved in and approves the adoption of the following procedures during Aon’s assessments:

The compensation committee utilizes these strategies when contemplating future executive compensation matters.

In 2024, Aon was retained to review the salaries, bonuses and equity plan levels and participation of executive employees, as well as equity plan levels and participation of employees below the executive level. Zymeworks’ management did not make or recommend such engagements and all such other services were approved by the compensation committee. Except as discussed below, Aon did not perform other services to the Company other than as a compensation consultant. The compensation committee determined Aon to be independent after evaluating the factors required under the applicable listing standard.

In addition to Aon’s services related to determining or recommending the amount or form of executive and non-employee director compensation, management has engaged Aon to perform unrelated broad-based compensation services and risk brokerage services (which included global risk in Canada and the United States). In 2024, fees paid to Aon for these unrelated broad-based compensation and risk brokerage services did not exceed $120,000 in the aggregate. The compensation committee was informed about these services.

Peer Companies and Use of Market Data

We compare our executive compensation program to those of a group of peer companies (North American biotechnology companies of a similar size and stage of development). The first step in the process is that the

41

compensation committee, with the support of Aon and management, reviews trends in biotechnology compensation practices and reviews and approves the list of peer companies used for benchmarking. As part of its analysis in 2023 related to 2024 compensation, Aon collected and analyzed compensation information from a comparative group of biotechnology companies, or peer group, approved by the compensation committee. The compensation committee evaluates the criteria used in establishing the peer group at least annually. The compensation committee seeks input from management in addition to Aon to ensure the peer group is consistent with our current business objectives and strategy.

The list of peer companies is approved based on various factors including industry classification, market capitalization, headcount and stage of development. In September 2023, with assistance from Aon, the compensation committee approved a peer group consisting of publicly traded, pre-commercial biopharmaceutical companies:

Based on these criteria, in September 2023, the compensation committee approved the following peer group set forth below and used this peer group to inform compensation decisions for 2024:

Our compensation committee uses comparative data from our peer group as a reference when setting and adjusting executive compensation, but it does not target our overall program or any particular element of compensation to be at a particular percentile compared to our peers. Rather, our compensation committee uses a range of peer group data for each executive position for which data is available, along with an assessment of each executive’s performance, criticality and tenure, to ensure that our executive compensation program and its constituent elements are and remain competitive in relation to our peers.

Components of Compensation Package

In 2024, our executive compensation program consisted of three major components:

42

In making 2024 compensation decisions, our compensation committee believed that each component of executive compensation must be evaluated and determined with reference to competitive market data, individual and Company-wide performance, our recruiting and retention goals, internal equity and consistency, and other information it deems relevant. As it evaluated executive compensation in 2024, the compensation committee believed that in the biopharmaceutical/biotechnology industry, long-term incentives such as stock options and restricted stock units are a primary motivator in attracting and retaining executives, in addition to salary and cash incentive bonuses.

The primary components of our 2024 executive compensation program are described in more detail below.

Base Salary

Annual base salary is designed to provide a competitive fixed rate of pay recognizing different levels of responsibility and performance within Zymeworks. This compensation component helps us to attract and retain highly qualified executives who have a history of proven success. In determining whether to increase the base salary for a particular executive, our compensation committee in discussions with our Chief Executive Officer (for executives other than the Chief Executive Officer) considers a variety of factors, including performance, length of service and criticality of role. The determination of base salary affects the amount of an executive’s cash bonus. The table below shows the base salaries of our named executive officers for 2024:

Cash Bonus

The cash bonus component is designed to provide our named executive officers with annual cash incentive awards based on achievement of certain goals and objectives. The awards represent pay at risk – they result in payment only if and to the extent certain goals and objectives are met – and do not affect decisions regarding other components of compensation. This compensation component motivates and rewards our named executive officers for outstanding performance. In addition, we occasionally provide sign-on bonuses to newly hired executives in order to induce them to join the Company. To this end, the Company provided Ms. Patterson with a $50,000 sign-on bonus, which was subject to repayment in full if, prior to September 1, 2025, Ms. Patterson had voluntarily left the Company for any reason or was terminated by us for cause (as defined in her employment agreement with us).

Annual cash incentive compensation for our named executive officers is paid pursuant to the Company’s Executive Incentive Compensation Plan, which provides the compensation committee discretion to make changes to performance targets and bonus targets, to decrease, increase or eliminate bonuses and to change other terms and conditions related to annual incentive compensation, in each case as the compensation committee deems appropriate to meet the overarching retention and incentive goals associated with our executive bonus program.

Named executive officers are eligible to receive an amount targeted at a pre-determined percentage of their base salary established at the beginning of each year. The compensation committee set annual target bonuses for each

43

of Mr. Galbraith and Dr. Moore in January 2024, and for Ms. Patterson in July 2024 at the time of her acceptance of the offer to become the Company’s Executive Vice President, Chief Business Officer and Chief Financial Officer, as follows:

At the beginning of each year, the compensation committee approves, or recommends that the Board of Directors approve, performance targets that are tied to the level of achievement of corporate and/or individual goals, and the compensation committee approves the weighting assigned to each goal. For 2024, the corporate and individual weighting was 100% corporate and 0% individual for all named executive officers. Achievement of corporate goals was a precondition for payment of bonuses with respect to 2024. Our compensation committee believed that this mix was appropriate in order to incentivize our management team to achieve our key corporate objectives.

After the end of the year, the compensation committee determines the performance bonus payable to each named executive officer based on the results achieved as compared to the performance targets established for a particular year. Depending on level of achievement, named executive officers may earn up to 150% of their respective target bonuses. There is no minimum bonus payable.

2024 Company Corporate Goals and Achievement

In December 2023, the Board of Directors (with input from members of the compensation committee) approved, and in January 2024, the members of the compensation committee updated, corporate goals for 2024 that were grouped into six main categories: (i) zanidatamab via the Jazz Partnership, (ii) zanidatamab via the BeiGene Partnership, (iii) early R&D (clinical), (iv) early R&D (preclinical), (v) ADVANCE and (vi) financing and partnerships. In addition, the leadership team had a seventh stretch goal relating to achievement of standards relating to corporate culture.

In January 2025, the compensation committee reviewed our performance against the corporate goals under the 2024 bonus plan, and determined that these goals were achieved at the 91.5% level. Additional detail on these goals and the assessed achievement is set forth in the table below:

44

45

The Company performed well against its 2024 corporate goals with respect to (i) zanidatamab via the Jazz Partnership, (ii) zanidatamab via the BeiGene Partnership, (iii) early R&D (clinical), (iv) early R&D (preclinical), and (v) ADVANCE, as well as its people/corporate culture goal. The Company did not achieve its 2024 corporate goals with respect to financing and partnerships, given changes in the competitive landscape and financial markets impacting the timing of potential partnerships and financing opportunities. Given the Company’s strong overall performance against its 2024 corporate goals, the compensation committee determined that these goals were achieved at the 91.5% level and approved 2024 bonuses for our named executive officers as follows:

Long-Term Incentives

Our Amended and Restated Stock Option and Equity Compensation Plan (the “Equity Compensation Plan”) authorizes us to make grants to eligible recipients of stock options, restricted stock, restricted stock units and other share-based awards, to attract, retain, motivate and reward qualified directors and employees and to enable and encourage such directors and employees to acquire shares of common stock as long-term investments.

46

The Company granted a mix of stock options and restricted stock units to Mr. Galbraith and Dr. Moore in January 2024. The compensation committee believes this approach aligns the interests of our executives (including those of our named executive officers) with our stockholders’ interests by rewarding for improvements in stock price over a period of time. The Company issues stock options and restricted stock units to reward for future performance and appreciation. Because stock options only have value if our stock price increases relative to the stock option’s exercise price, we consider them to be an important performance-based tool that encourages our named executive officers to focus on driving increases to stockholder value. Restricted stock units play an important role in our executive compensation program because they provide some value even during periods of stock price or market volatilities, provide retention incentives during the vesting period, and reinforce a culture of ownership. By granting restricted stock units, the Company can also reduce the dilutive effect of the equity incentive awards in the form of stock options, which benefits our stockholders over time. In addition, the vesting feature of our stock awards contributes to executive retention by providing an incentive to our executives to remain employed by us during the vesting period. For 2024, we determined that annual grants to Mr. Galbraith and Dr. Moore in the form of an approximately 50/50 value mix of stock options and restricted stock units was most appropriate to reflect the continued change in the market and the evolution of our compensation program away from an options-only approach. The compensation committee evaluates the long-term incentive programs for each year, and the appropriate mix of equity awards to grant to our executive officers for the applicable year. In future years or for particular executives, the compensation committee may approve a different mix of equity awards if it determines necessary or appropriate to achieve our compensation objectives.

After considering its compensation objectives and negotiations with Ms. Patterson regarding her joining the Company, the compensation committee approved an initial award of stock options for Ms. Patterson shortly after her commencement of employment with the Company. The compensation committee believed that awarding Ms. Patterson’s initial equity grant solely in the form of options, consistent with its past practice with respect to the hiring of executives, would provide Ms. Patterson with strong incentives to increase stockholder value, and that given her role as our Chief Business and Financial Officer, this was appropriate for her new hire award. For 2025, the compensation committee has granted Ms. Patterson’s annual equity awards in a combination of options and restricted stock units in the same proportions as our other named executive officers, to balance the performance-based incentives of stock options with the retention, reward and culture of ownership benefits of restricted stock units.

For the stock options, the option exercise price may not be less than the closing price of our common stock on the date of grant. For the 2024 stock option grants to our named executive officers, 25% of the granted options is scheduled to vest on the first anniversary of grant date (subject to continued service and any applicable acceleration of vesting provisions in their employment agreements, as described below). On the last day of each month thereafter, a further 1/36^th of the total number of remaining granted options is scheduled to vest. These options are subject to any applicable acceleration provisions in the Equity Compensation Plan or in the named executive officer’s employment agreement.

Each restricted stock unit represents the right to receive one share of our common stock upon vesting of that unit, without the payment of an exercise price or other cash consideration for the issued shares of common stock. For the 2024 restricted stock unit grants to Mr. Galbraith and Dr. Moore, 1/3^rd of the restricted stock units are scheduled to vest on each anniversary of the grant date (subject to the named executive officer’s continued service and subject to any applicable acceleration provisions in the Equity Compensation Plan or in the named executive officer’s employment agreement).

47

The following table shows information regarding stock option and restricted stock unit grants to each of our named executive officers made during the year ended December 31, 2024:

Previous grants are taken into account when considering new option and restricted stock unit grants, as well as other factors such as market data, retention and incentive considerations, internal equity, Company performance and prior and expected future individual contributions. Decisions regarding long-term incentives do not affect decisions regarding other components of compensation.

Benefits and Perquisites

Other compensation to our named executive officers primarily consists of participation in our broad-based employee benefit plans. Named executive officers are eligible to participate in all our employee benefit plans, in each case on the same basis as other employees in the entity in which they are employed, including a retirement savings plan for those employed in Canada, a 401(k) plan for those employed in the United States, and pension plans for those employed in Ireland and the UK. Our named executive officers also are eligible to participate in our employee stock purchase plan on the same terms as our other eligible employees.

Currently, we do not view perquisites or other personal benefits as a material component of our executive compensation program. However, we do provide certain perquisites to our named executive officers in situations where we believe it is appropriate to assist an individual in the performance of his or her duties, to make them more efficient and effective, and for recruitment and retention purposes.

In addition, consistent with our philosophy regarding personal benefits, and as further described in “Executive Compensation –Executive Employment Arrangements and Potential Payments upon Termination or Change in Control,” to encourage and facilitate Dr. Moore’s relocation to Canada, we provide him with certain

48

reimbursements for relocation expenses, as well as a gross-up to make sure such payments are tax neutral to him, tax equalization payments to neutralize any increase in his taxes as a result of his relocation, and tax preparation assistance for two years following his relocation. The compensation committee believes these benefits were appropriate to enable a smooth relocation for Dr. Moore and to allow him to keep his focus on the business rather than on the costs and burdens of the relocation.

We also provide certain personal benefits to Mr. Galbraith, which were negotiated as part of Mr. Galbraith’s initial January 2022 employment agreement and subsequent amendments, including the most recent amendment in January 2024. These benefits were provided in order to induce him to initially join and later to remain with the Company and to increase his ability to work efficiently. These benefits include certain housing, travel, relocation, and certain tax equalization and gross-up benefits, as described in “Executive Compensation – Executive Employment Arrangements and Potential Payments upon Termination or Change in Control.” In late 2022 and again in January 2024, we amended Mr. Galbraith’s employment agreement to extend the time period for certain benefits, as described in “Executive Compensation – Executive Employment Arrangements and Potential Payments upon Termination or Change in Control.” The compensation committee approved the extension of these benefits as it believed that doing so would assist Mr. Galbraith in the continued performance of his duties and continue to aid in his efficiency.

In the future, we may continue to provide perquisites or other personal benefits in circumstances where we believe it is appropriate to assist an individual named executive officer in the performance of his or her duties, to make him or her more efficient and effective, and for recruitment, motivation or retention purposes.

Potential Payments upon Termination or Change in Control

Certain of our executives, including each of our named executive officers, are parties to employment agreements with us which set forth conditions of employment and the payments that will be made upon termination of their employment. Additional discussion of the employment agreements with our named executive officers is set forth below under “Executive Compensation – Executive Employment Arrangements and Potential Payments upon Termination or Change in Control.” We believe that these protections are necessary to provide our valuable named executive officers with incentives to forgo other employment opportunities and to maintain continued focus and dedication to their responsibilities to maximize stockholder value, including if there is a potential transaction that could involve a change in control, without undue concern that the officer will be terminated and lose his or her income and benefits. We believe the level of severance and change in control benefits provided is appropriate and is necessary to attract and retain key employees.

Summary Compensation Table

The following table presents the compensation awarded to, earned by or paid to each of our named executive officers for the years ended December 31, 2024 and December 31, 2023. We do not have non-qualified deferred compensation.

49

50

Outstanding Equity Awards at 2024 Year End

The following table lists all outstanding equity awards granted in U.S. dollars under the Equity Compensation Plan and our Inducement Stock Option and Equity Compensation Plan (the “Inducement Plan”) held by our named executive officers as of December 31, 2024:

51

Pension Benefits

We do not have any qualified or non-qualified defined benefit pension plans.

Defined Contribution Plans

Registered Retirement Savings Plan

Our executive officers resident in Canada are eligible, along with all other employees resident in Canada, to participate in our registered retirement savings plan (“RRSP”) matching program. Under this program, we match the amount contributed by each employee into a group RRSP plan, up to a pre-determined percentage of annual salary. We match employee contributions to the group RRSP up to 6.0% of annual salary. Generally, company matching contributions will not exceed 50% of the maximum annual RRSP dollar limit as specified by the Canada Revenue Agency in any given year.

401(k) Plan

Our executive officers resident in the United States are eligible, along with all other U.S.-based employees, to participate in a 401(k) matching program. Under this program, we match the amount contributed by each employee into a 401(k) plan, up to a predetermined percentage of annual salary. We match employee contributions to a 401(k) plan up to 6.0% of annual salary, with company matching contributions not to exceed the annual personal and Age 50 Catch Up contribution limit (if applicable) set by the Internal Revenue Service, or the IRS, in any given year.

Group Personal Pension Plan

Our executive officers resident in the UK are eligible, along with all other employees resident in the UK, to participate in our group personal pension (“GPP”) plan matching program. Under this program, we match the amount contributed by each employee into a GPP plan, up to a pre-determined percentage of annual salary. We match employee contributions to a GPP plan up to 6.0% of annual salary. Generally, company matching contributions will not exceed 50% of the maximum annual plan dollar limit set by His Majesty’s Revenue and Customs, or HMRC, in any given year.

Non-qualified Deferred Compensation

We do not have any non-qualified defined contribution plans or other deferred compensation plans.

Executive Employment Arrangements and Potential Payments upon Termination or Change in Control

Executive Employment Arrangements

Key provisions of the employment agreements that were in effect as of December 31, 2024, for our named executive officers are described below.

Kenneth Galbraith

In connection with Mr. Galbraith’s appointment as President and Chief Executive Officer in January 2022, Mr. Galbraith entered into an employment agreement with us (the “Original Agreement”), on December 30, 2022, Zymeworks BC and Zymeworks Management Inc., our subsidiaries, and Mr. Galbraith entered into an amendment to the Original Agreement (the “First Amendment”), and on January 3, 2024, Zymeworks BC and Mr. Galbraith entered into a second amendment (the “Second Amendment”, and the Original Agreement, as amended by the First Amendment and the Second Amendment, the “Galbraith Employment Agreement”). The Galbraith Employment Agreement does not have a specific term. The Second Amendment established Mr. Galbraith’s principal place of employment as the UK, or another location as agreed upon between the parties, which removes the requirement for Mr. Galbraith to relocate to Vancouver, British Columbia or Seattle, Washington, and incorporated certain extensions of compensation and benefit provisions, as described below.

52

Pursuant to the Galbraith Employment Agreement, Mr. Galbraith is entitled to the following compensation and benefits:

53

On March 31, 2024, Mr. Galbraith was appointed interim Chief Financial Officer and continued in his roles as Chair of the Board of Directors, President and Chief Executive Officer and assumed the duties of principal financial officer and principal accounting officer, without any changes to his compensatory arrangements. In connection with Ms. Patterson’s start date, Mr. Galbraith resigned from the positions of interim Chief Financial Officer and as principal financial officer and principal accounting officer of the Company, effective September 1, 2024. The compensatory and other material terms of Mr. Galbraith’s employment with the Company were unchanged in connection with his appointment and subsequent resignation as interim Chief Financial Officer, principal financial officer and principal accounting officer.

Leone Patterson

On July 19, 2024, our subsidiary ZBI entered into an employment agreement with Ms. Patterson, which became effective September 1, 2024, setting forth the terms and conditions of her employment as Executive Vice President, Chief Business Officer and Chief Financial Officer of the Company (the “Patterson Employment Agreement”). The Patterson Employment Agreement does not have a stated term.

Pursuant to the Patterson Employment Agreement, Ms. Patterson is entitled to the following compensation and benefits:

54

In addition, if any of the payments or benefits provided for under the Patterson Employment Agreement or otherwise payable to Ms. Patterson would constitute “parachute payments” within the meaning of Section 280G of the Code and would be subject to the related excise tax, she would be entitled to receive either full payment of such payments and benefits or such lesser amount that would result in no portion of the payments and benefits being subject to the excise tax, whichever results in the greater amount of after-tax benefits to her. The Patterson Employment Agreement does not require us to provide any tax gross-up payments to her.

Paul Moore

On July 18, 2022, the Company and our subsidiary ZBI entered into an employment agreement with Dr. Moore setting forth the terms and conditions of his employment as Chief Scientific Officer of the Company (the “Initial Employment Agreement”). In connection with Dr. Moore’s planned relocation from the United States to Canada, the Company and our subsidiary Zymeworks BC entered into an amended and restated employment agreement with Dr. Moore in July 2023 (the “Moore Employment Agreement”) that supersedes and replaces the Initial Employment Agreement. The Moore Employment Agreement does not have a stated term.

Pursuant to the Moore Employment Agreement, Dr. Moore is entitled to the following compensation and benefits:

55

In addition, if any of the payments or benefits provided for under the Moore Employment Agreement employment agreement or otherwise payable to Dr. Moore would constitute “parachute payments” within the meaning of Section 280G of the Code and would be subject to the related excise tax, he would be entitled to receive either full payment of such payments and benefits or such lesser amount that would result in no portion of the payments and benefits being subject to the excise tax, whichever results in the greater amount of after-tax benefits to him. The Moore Employment Agreement does not require us to provide any tax gross-up payments to him.

56