Sinovac's Special Meeting of Shareholders is Just Days Away; Your Vote Matters No Matter How Many Shares You Own

SAIF Partners Urges Shareholders to Vote the GOLD Proxy Card "FOR" its Director Candidates to End Years of Chaos, Restore Credibility and Unlock Long-Term Value for All Sinovac Shareholders

SAIF Partners IV L.P., ("SAIF Partners", "we" or "us"), the largest single investor in Sinovac Biotech Ltd. ("Sinovac" or the "Company") which beneficially owns approximately 15% of the Company's outstanding common shares, today urged shareholders to immediately vote "FOR" the election of SAIF Partners' ten highly qualified director candidates to the Company's Board of Directors (the "Board") using the GOLD proxy card. Sinovac's Special Meeting of Shareholders (the "Special Meeting") – scheduled for Tuesday, July 8 at 8:00 p.m. Atlantic Standard Time (Wednesday, July 9 at 8:00 a.m. China Standard Time) – is just days away, and time is running out to cast your vote for change.

SAIF Partners firmly believes that Sinovac's current Board – the majority of whose members were not duly elected by shareholders or sanctioned by the Privy Council – does not act in the interests of all shareholders, and in fact only began to do so when it was publicly pressured. Further, we believe the current Board lacks integrity, industry experience, management expertise, and respect for the law necessary to fulfill its lofty promises to shareholders. As such, we do not believe the current Board has the capability to resolve the Company's most pressing issues, including concluding its numerous lawsuits and ending the six-year suspension of the trading of Sinovac's common shares in the public markets.

Most importantly, however, we are highly skeptical of the current Board's ability to follow through on its plan to issue significant dividends to shareholders for several concerning reasons. These include the current Board's failure to actively engage with management, its lack of sound financial reasoning for its proposed dividend figures, its apparent unwillingness to hire a new independent auditor after it drove Sinovac's prior public accounting firm to resign in April, its poor governance practices, and several of its recent members' unethical and illegal actions in recent years, including securities violations by former director Chiang Li. These issues, among others, lead us to believe that the current Board has put forth its massive dividend distribution plan simply to win shareholders' support and retain their positions, even though it lacks the capabilities to follow through on its stated promise.

Ultimately, we believe that meaningful change is urgently needed on Sinovac's Board to restore the Company's credibility with investors and regulators and unlock the tremendous long-term value embedded within Sinovac for all shareholders. If elected, our nominees will work closely with management to deliver shareholders the long-overdue dividends they deserve and establish a long-term business strategy that will maximize the value of the Company for all shareholders.

Now is Your Chance to Elect a Board that Will Act in the Best Interest of ALL Sinovac Shareholders

Vote the GOLD Proxy Card Today "FOR" Proposal 1 and Proposal 2 to Remove Sinovac's Current Board and Elect SAIF Partners' Highly Qualified Director Candidates

VISIT WWW.PROXYVOTE.COM TO CAST YOUR VOTE USING YOUR UNIQUE CONTROL NUMBER LOCATED ON YOUR GOLD PROXY CARD.

IF YOU RECEIVED A GOLD PROXY CARD BY EMAIL, CLICK THE LINK IN YOUR EMAIL TO CAST YOUR VOTE

IF YOU DID NOT RECEIVE A GOLD PROXY CARD OR IF YOU HAVE LOST YOUR GOLD PROXY CARD, CHECK YOUR SPAM FOLDER OR CONTACT YOUR BROKER TO ASK FOR YOUR CONTROL NUMBER.

IF YOU HAVE ALREADY VOTED USING THE COMPANY'S WHITE PROXY CARD, YOU CAN STILL CHANGE YOUR VOTE BY USING YOUR GOLD PROXY CARD.

About SAIF Partners

SAIF Partners is a leading Asian private equity firm with cumulative assets under management of over $4 billion. SAIF Partners is an active lead investor working closely with its portfolio companies to develop their business both organically and through acquisitions, seeking synergistic cooperation among them, as well as enhancing shareholder value via promotion of good corporate governance and best management practices.

Additional Information and Where to Find It

This communication may be deemed to be solicitation material in respect of SAIF Partners' nomination of ten director nominees to Sinovac's Board. In connection with such solicitation, SAIF Partners mailed the definitive proxy statement and proxy card to shareholders of Sinovac with respect to the Special Meeting to be held in connection with the election of directors to Sinovac's Board. The definitive proxy statement mailed by SAIF Partners is also filed as Exhibit 1 to its Schedule 13D/A filed on or about June 16, 2025. SHAREHOLDERS ARE URGED TO READ THE PROXY STATEMENT (INCLUDING ANY AMENDMENTS OR SUPPLEMENTS THERETO) AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC IN CONNECTION WITH SINOVAC'S SPECIAL MEETING, INCLUDING ANY DOCUMENT INCORPORATED BY REFERENCE THEREIN, CAREFULLY IF AND WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE DIRECTOR NOMINEES AND THE SPECIAL MEETING AND RELATED MATTERS. Sinovac's shareholders may obtain, free of charge, the definitive version of the proxy statement, any amendments or supplements thereto, and any other relevant documents mailed by SAIF Partners in connection with the Special Meeting at proxyvoting.com/SVA/documents.

View source version on businesswire.com: https://www.businesswire.com/news/home/20250702781089/en/

Media Contacts

Jonathan Gasthalter/Mark Semer/Grace Cartwright

Gasthalter & Co.

+1 (212) 257 4170

SAIF@gasthalter.com

Investor Contacts

Paul Schulman/Bill Dooley/Jon Eyl

Sodali & Co.

+ 1 (203) 658-9400

SAIF@info.sodali.com

SAIF Partners: Now is Your Last Chance to Vote for Board Change at Sinovac