SINOVAC Board Wins New York Legal Battle Against Advantech/Prime

New York Court Denies Advantech/Prime’s Petition for Emergency Injunctive Relief

Clears Legal Hurdle for Dividend Paying Agent to Payout the Special Cash Dividend of $55.00 Per Common Share on July 7, 2025

BEIJING – In a significant victory, SINOVAC Biotech Ltd. (SVA), a prominent player in the biopharmaceutical sector in China, has successfully navigated a legal challenge in the U.S. District Court for the Southern District of New York. The court denied Advantech/Prime Success’ (“Advantech/Prime”) petition for emergency injunctive relief, a move that could pave the way for a substantial payout to shareholders.

This ruling in New York marks another setback for Advantech/Prime, acting in concert with Vivo Capital (collectively the “Dissenting Investor Group”). Their campaign to gain control of SINOVAC is facing continued resistance by the company’s recently installed, lawfully-elected Board of Directors (“current SINOVAC Board”). The current board is operating in accordance with the Privy Council order and Antiguan Law. The court’s decision also thwarts any attempts to block the $55.00 per common share special cash dividend declared by the current SINOVAC Board.

With the New York court’s endorsement, the current SINOVAC Board is now free to continue its legal actions in Antigua. The board seeks to invalidate the PIPE shares improperly issued to the Dissenting Investor Group by the previous, illegitimate board (“Imposter Former Board”). Should the current SINOVAC Board prevail in the legal proceedings, it has announced plans to distribute an additional $11.00 per common share to SINOVAC’s legitimate shareholders.

Dr. Chiang Li, Chairman of the SINOVAC Board, stated, “We are unwavering in our commitment to restore fairness. We will deliver value to all valid SINOVAC shareholders, starting with the $55.00 per share special cash dividend as early as July 7, 2025.”

The Dissenting Investor Group’s confrontational legal strategy is transparent: To stall any shareholder dividend payments unless their invalid PIPE shares receive the same allocation, a move that is particularly egregious given they have already pocketed over $1 billion in dividends from a SINOVAC operating subsidiary. The current SINOVAC Board has set aside in escrow the pro rata share of dividends earmarked for the PIPE shares, funds the Dissenting Investor Group could potentially receive were their legal actions successful. The current SINOVAC Board is taking the fight to them – and winning. “We are working to ensure all valid shareholders receive their fair share,” said Dr. Chiang Li.

Your Vote is Important

Your vote, due on or before July 8th, is about the future of SINOVAC and impacts your dividend payments.

The current SINOVAC Board urges shareholders to vote on the WHITE proxy card “AGAINST” Proposal 1, aimed at ousting the current Board, and “AGAINST” Proposal 2, to appoint the Reconstituted Imposter Board Slate. Your vote is critical to maintaining SINOVAC’s course toward stability, expansion, and shareholder value.

DISCARD any materials advising a vote for the Reconstituted Imposter Former Board Slate. If you have already cast a vote for the Reconstituted Imposter Former Board Slate, you can change it by using the WHITE proxy card or WHITE voting instruction form to vote again. Only your most recent vote will be counted!

About SINOVAC

Sinovac Biotech Ltd. (SINOVAC) is a China-based biopharmaceutical company focused on the research, development, manufacturing, and commercialization of vaccines to protect against human infectious diseases.

SINOVAC’s portfolio includes vaccines for COVID-19, enterovirus 71 (EV71) infected Hand-Foot-Mouth disease (HFMD), hepatitis A, varicella, influenza, poliomyelitis, and pneumococcal disease, among others.

The COVID-19 vaccine, CoronaVac®, has received approval in over 60 countries and regions worldwide. The hepatitis A vaccine, Healive®, met WHO prequalification standards in 2017. The EV71 vaccine, Inlive®, an innovative vaccine under the “Category 1 Preventative Biological Products” classification, was commercialized in China in 2016. In 2022, SINOVAC’s Sabin-strain inactivated polio vaccine (sIPV) and varicella vaccine received WHO prequalification.

SINOVAC was the first to receive approval for its H1N1 influenza vaccine Panflu.1®, supplying the Chinese government’s vaccination campaign. The Company is also the sole provider of the H5N1 pandemic influenza vaccine, Panflu®, to the Chinese government’s stockpiling program.

SINOVAC continues to invest in new vaccine R&D, expanding with more combination vaccine products in development and is exploring global market prospects. The company intends to expand trade opportunities and partnerships internationally.

Important Additional Information and Where to Find It

In connection with SINOVAC’s Special Meeting, have filed with the U.S. Securities and Exchange Commission (“SEC”) and mailed to shareholders of record entitled to vote at the Special Meeting a definitive proxy statement and other documents, including a WHITE proxy card. SHAREHOLDERS ARE ENCOURAGED TO READ THE PROXY STATEMENT AND ALL OTHER RELEVANT DOCUMENTS WHEN FILED WITH THE SEC AND WHEN THEY BECOME AVAILABLE BECAUSE THOSE DOCUMENTS WILL CONTAIN IMPORTANT INFORMATION. Investors and other interested parties will be able to obtain the documents free of charge at the SEC’s website, www.sec.gov, or from SINOVAC at its website: https://www.sinovac.com/en-us/Investors/sec_filings. You may also obtain copies of SINOVAC’s definitive proxy statement and other documents, free of charge, by contacting SINOVAC’s Investor Relations Department at [email protected].

Safe Harbor Statement

This announcement contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and as defined in the U.S. Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified by terminology such as “may,” “will,” “expect,” “anticipate,” “aim,” “estimate,” “intend,” “plan,” “believe,” “potential,” “continue,” “is/are likely to” or other similar expressions. Such statements are based upon current expectations and current market and operating conditions and relate to events that involve known or unknown risks, uncertainties and other factors, all of which are difficult to predict and many of which are beyond the Company’s or Board’s control, which may cause actual results, performance or achievements to differ materially from those in the forward-looking statements. Further information regarding these and other risks, uncertainties or factors is included in the Company’s filings with the U.S. Securities and Exchange Commission. The Company and Board do not undertake any obligation to update any forward-looking statement as a result of new information, future events or otherwise, except as required under law.

SINOVAC Board Wins New York Legal Battle Against Advantech/Prime