Avista Public Acquisition Corp. II And OmniAb Business Combination Approved By APAC Shareholders Closing Scheduled for November 1;

APAC Shareholder Approval Obtained, Closing Scheduled for November 1, 2022

Ligand "Regular Way" and "Ex-Distribution" and OmniAb "When-Issued" Set to Begin Trading on October 25, 2022

Ligand Pharmaceuticals Incorporated (NASDAQ:LGND) today announced the business combination (Business Combination) of Avista Public Acquisition Corp. II (APAC) (NASDAQ:AHPA) and OmniAb, Inc. (OmniAb), was approved by APAC shareholders in a vote held this morning, with 96% of the shares represented in person, virtually or by proxy voting in favor of the combination. Based on actual redemptions and estimated expenses, OmniAb expects to have approximately $95 million of net cash upon the closing of the Business Combination (Closing). Prior to the Business Combination, APAC will domesticate in Delaware and change its name to OmniAb, Inc. (New OmniAb).

The spin-off of OmniAb from Ligand remains on track with an expected closing on November 1, 2022, subject to the satisfaction or waiver of closing conditions for the Business Combination. The record date (Record Date) for the dividend of shares of common stock of OmniAb to be distributed to Ligand shareholders (Distribution) is October 26, 2022, and the Distribution is expected to be made on November 1, 2022 immediately prior to the Business Combination, subject to the satisfaction or waiver of closing conditions.

Ligand shareholders as of the close of business on the Record Date will receive shares of OmniAb common stock on a pro rata basis representing 100% of Ligand's interest in OmniAb. Immediately following the Distribution of OmniAb shares, OmniAb will merge (Merger) with APAC's wholly-owned subsidiary and be the surviving company. Pursuant to the Merger, all shares of OmniAb common stock will be automatically exchanged for shares of New OmniAb on a pro rata basis according to a base exchange ratio (Base Exchange Ratio) calculated immediately prior to Closing using a formula set forth in the merger agreement (Merger Agreement) among Ligand, OmniAb, APAC and a subsidiary of APAC. The Base Exchange Ratio is based on the number of shares of OmniAb common stock outstanding immediately prior to Closing calculated using the treasury stock method with the number of equity awards being allocated to OmniAb in the Distribution calculated based on the relative trading values of Ligand common stock in the "regular way" and "ex-distribution" markets during the five-trading-day period prior to the Closing.

Based on an illustrative record date of June 30, 2022, the Ligand stock price as of such date and an estimated Base Exchange Ratio, Ligand shareholders would receive approximately 4.9 shares of New OmniAb common stock for each share of Ligand common stock.

In addition, as part of the exchange, Ligand shareholders as of the Record Date will receive earnout shares of New OmniAb common stock (Earnout Shares) on a pro rata basis according to an earnout exchange ratio (Earnout Exchange Ratio) calculated immediately prior to the Closing using a formula set forth in the Merger Agreement. Based on an illustrative record date of June 30, 2022, the Ligand stock price as of such date and an estimated Earnout Exchange Ratio, Ligand shareholders would receive approximately 0.75 Earnout Shares for each share of Ligand common stock. The Earnout Shares will vest based upon the achievement of certain volume-weighted average trading prices (VWAP) for shares of New OmniAb for any 20 trading days over a consecutive 30 trading-day period during the five-year period following the Closing. The Earnout Shares will vest (i) with respect to fifty percent of such Earnout Shares, upon achievement of a VWAP of $12.50 per share of New OmniAb common stock or upon the occurrence of a change of control transaction that will result in the holders of New OmniAb common stock receiving a price per share in excess of $12.50, and (ii) with respect to the remaining fifty percent of the Earnout Shares, upon achievement of a VWAP of $15.00 per share of New OmniAb common stock or upon the occurrence of a change of control transaction that will result in the holders of New OmniAb common stock receiving a price per share in excess of $15.00. After the Earnout Shares are distributed to stockholders pursuant to the Distribution, the Earnout Shares will not be transferrable until the vesting condition for the applicable tranche of Earnout Shares has been achieved.

The actual number of shares of New OmniAb common stock and Earnout Shares that each Ligand shareholder will receive with respect to each share of OmniAb common stock will be calculated on the closing date and may differ from these estimates. No fractional shares of New OmniAb common stock will be issued in the merger, and instead Ligand shareholders will receive cash in lieu of any fractional share (other than with respect to Earnout Shares, which will be rounded down to the nearest share).

Ligand shareholders do not need to take any action to receive their pro rata consideration in the Business Combination. Their OmniAb shares received upon Distribution of the dividend will automatically be exchanged for New OmniAb common stock and Earnout Shares in the Merger on the closing date of the Business Combination. Following the Closing, Ligand shareholders will continue to hold, along with their new shares of New OmniAb common stock and Earnout Shares, the same number of shares of Ligand common stock that they held immediately prior to the Closing. After the Closing, investors should expect that Ligand's share price will adjust to reflect the transfer of the OmniAb business to New OmniAb.

In connection with the Business Combination, OmniAb and APAC filed registration statements with the Securities and Exchange Commission (SEC), described below under "Important Information and Where to Find It." On September 30, 2022, the SEC declared both registration statements effective. The registration statements contain further information regarding the spin-off and Business Combination, including the conditions to completion of the Business Combination, estimated transaction and other expenses and additional details regarding the calculation of the applicable exchange ratios described above.

Factors that May Affect the Dividend and Spin-Off

The dividend is conditioned upon, and the spin-off and Business Combination are subject to, the satisfaction or waiver of closing conditions for the Business Combination. If certain closing conditions are not satisfied or waived in advance of the expected closing date, Ligand may elect to change the record date for the dividend to a later date or to not proceed with the dividend or the spin-off.

Two-Way Trading to Begin for Ligand on the Nasdaq Global Market (Nasdaq)

Beginning on or around the trading day prior to the Record Date and continuing through the close of trading on the closing date of the Business Combination, there will be two markets in Ligand common stock on Nasdaq: a "regular way" market and an "ex-distribution" market. During this period of two-way trading in Ligand common stock, there will also be a market on Nasdaq for New OmniAb common stock on a "when issued" basis.

The trading options that will be available during the two-way trading period are:

Ligand Regular Way Trading

If, during the period of two-way trading, a Ligand shareholder sells a share of Ligand common stock in the regular way market under Ligand's Nasdaq symbol, "LGND," the shareholder will be selling both the share of Ligand common stock and the right to receive the Distribution of OmniAb common stock (which will be exchanged for shares of New OmniAb common stock and Earnout Shares in the transaction). On the trading day after the Closing, shares of Ligand common stock will commence trading without the right to receive the Distribution. At that time, the Earnout Shares will not be tradable and will remain non-transferrable until the vesting condition for the applicable tranche of Earnout Shares has been achieved.

Ligand Ex-distribution Trading

If, during the period of two-way trading, a Ligand shareholder sells a share of Ligand common stock in the ex-distribution market under the temporary Nasdaq symbol "LGNDV," the Ligand shareholder will be selling only a share of Ligand common stock and will retain the right to receive the Distribution of OmniAb common stock (which will be exchanged for shares of New OmniAb common stock and Earnout Shares in the transaction).

New OmniAb When-issued Trading

During the two-way trading period, there will also be a market in shares of New OmniAb common stock on a when-issued basis under the temporary Nasdaq symbol "OABIV."

Trades under the symbols "OABIV" and "LGNDV" will settle after the closing date of the Business Combination. If the transaction is not completed, all trades made under these temporary symbols will be cancelled.

In all cases, investors should consult with their financial and tax advisors regarding the specific implications of selling shares of their Ligand common stock or the right to receive shares of New OmniAb common stock and Earnout Shares on or before the closing date of the Business Combination.