SINOVAC Board of Directors Provides Update on Special Dividend Payment and Commitment to Delivering Value to All Shareholders Accelerates payment of previously announced special cash dividend of US$55.00 per common share

SINOVAC Board of Directors Provides Update on

Special Dividend Payment and Commitment to Delivering Value to All Shareholders

Accelerates payment of previously announced

special cash dividend of US$55.00 per common share

Decides to declare second special cash dividend

of US$19.00 per common share

Intends to declare third special cash dividend

between US$20.00 - US$50.00 per common share

Adopts new dividend policy to regularly return

cash to shareholders

BEIJING, June 17, 2025 - The Board

of Directors of SINOVAC Biotech Ltd. (NASDAQ: SVA) ("SINOVAC" or the "Company"), a leading provider

of biopharmaceutical products in China, today announced several important decisions to deliver sustainable value to shareholders and strengthen

the Company's governance framework.

Currently, a dissenting investor group led by Advantech/Prime Success

and Vivo Capital (together known as the "Dissenting Investor Group") and certain former illegitimate board (the "Imposter

Board") members are attempting to distract SINOVAC shareholders with lawsuits, false claims and empty promises as part of a hostile

attempt to remove the SINOVAC Board - which was recently installed by the Privy Council order and in accordance with Antiguan law

- with the goal to move SINOVAC backward and continue to entrench themselves. In contrast, the SINOVAC Board is taking clear actions

to restore fairness and deliver value to ALL SINOVAC shareholders.

Key Updates and Commitments

SINOVAC Board has authorized Audit Committee Chair Sven H. Borho to accelerate the payment of the previously announced

special dividend of US$55.00 per common share, which it now expects to be paid on or about July 7, 2025, in advance of the Special

Shareholder Meeting ("SSM"), subject to compliance with and approval by NASDAQ and the outcome of the Advantech/Prime Success

lawsuit recently filed in New York.

to claims by the Dissenting Investor Group, the date of the SSM on July 8 was driven by when SAIF filed the requisition for the

meeting, and per Antiguan law, the SSM has to be held by July 8 unless SAIF agrees to resend their request. The SINOVAC Board has

asked SAIF to reissue the request so that the SSM can be delayed until after July 9, but received no reply. Nevertheless, since

establishing the date for the SSM, the Board has been working to accelerate the payment of the special dividend, demonstrating our commitment

to restoring fairness. Yet the SINOVAC Board has encountered frequent interference by the Dissenting Investor Group, including the new

lawsuit filed by Advantech/Prime Success on June 12.

The SINOVAC Board's acceleration of this payment is

to ensure that, regardless of the outcome of the SSM, all valid shareholders will receive the special dividend payment as an initial corrective

step in ensuring fair and equitable distributions of dividends to all SINOVAC shareholders.

This policy is another step the SINOVAC Board is taking to

make common shareholders whole and restore fairness and equity for all valid shareholders who were previously excluded from distributions.

The Imposter Board allowed SLS to distribute over US$2 billion in dividends to minority shareholders but determined not to distribute

a fair share to the valid common shareholders of SINOVAC. Under the current SINOVAC Board, this practice will stop - if there are

distributions made at the subsidiary level, we will ensure they will be fairly distributed to all SINOVAC shareholders.

current SINOVAC Board directors are focused on completing the SSM and fighting for fairness for ALL shareholders, in furtherance of the

Company's best interests. Following the SSM, the SINOVAC Board will immediately turn towards improving SINOVAC's corporate

governance. To that end, the SINOVAC Board is committed to holding an annual meeting of shareholders in the second quarter of 2026. Ahead

of this meeting, the SINOVAC Board will introduce additional director nominees for election, ensuring the full slate has the combined

skills, qualifications, and experience to best serve and oversee the Company's strategy and operations, with the integrity and fiduciary

commitment to fairly represent and make decisions in the best interests of the Company, while duly considering the interests of all SINOVAC

shareholders. The slate is expected to include one or more representatives from SINOVAC's management team, ensuring that the SINOVAC

Board and management remain aligned on the Company's long-term strategic goals.

The SINOVAC Board also authorized the formal exploration

of a future listing of SINOVAC shares on The Stock Exchange of Hong Kong and potentially other exchanges in order to stimulate liquidity,

mitigate geopolitical risk, and maximize long term shareholder value.

Your Vote Will be Important

As previously announced, the Company intends

to imminently file its definitive proxy materials with the Securities and Exchange Commission (SEC) for the Special Meeting of Shareholders

to be held on Wednesday, July 9, 2025 at 8:00 a.m. China Standard Time (Tuesday, July 8, 2025 at 8:00 p.m. Atlantic

Standard Time). Valid shareholders of record as of the close of business on May 19, 2025 are entitled to vote at the meeting.

Your vote on or before July 9 will be about the future of SINOVAC,

your receipt of your make-whole dividend payments in the near-term, and the long-term value of your investment.

Your vote will be critical to ensuring that SINOVAC remains on the

path to stability, growth, and value creation for all shareholders.

Sinovac Biotech Ltd. (SINOVAC) is a China-based biopharmaceutical company

that focuses on the R&D, manufacturing, and commercialization of vaccines that protect against human infectious diseases.

SINOVAC's product portfolio includes vaccines against COVID-19, enterovirus

71 (EV71) infected Hand-Foot-Mouth disease (HFMD), hepatitis A, varicella, influenza, poliomyelitis, pneumococcal disease, etc.

The COVID-19 vaccine, CoronaVac , has been approved for use in

more than 60 countries and regions worldwide. The hepatitis A vaccine, Healive , passed WHO prequalification requirements in 2017.

The EV71 vaccine, Inlive , is an innovative vaccine under "Category 1 Preventative Biological Products" and commercialized

in China in 2016. In 2022, SINOVAC's Sabin-strain inactivated polio vaccine (sIPV) and varicella vaccine were prequalified by the WHO.

SINOVAC was the first company to be granted approval for its H1N1 influenza

vaccine Panflu.1 , which has supplied the Chinese government's vaccination campaign and stockpiling program. The Company is also the

only supplier of the H5N1 pandemic influenza vaccine, Panflu , to the Chinese government stockpiling program.

SINOVAC continually dedicates itself to new vaccine R&D, with more

combination vaccine products in its pipeline, and constantly explores global market opportunities. SINOVAC plans to conduct more extensive

and in-depth trade and cooperation with additional countries, and business and industry organizations.

Important Additional Information

and Where to Find It

with SINOVAC's Special Meeting, SINOVAC will file with the U.S. Securities and Exchange Commission ("SEC") and mail

to shareholders of record entitled to vote at the Special Meeting a 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. When filed with the SEC, the proxy statement and WHITE proxy card

will also be mailed to shareholders of record. 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 proxy statement and other documents, free of charge, by contacting SINOVAC's Investor

Relations Department at ir@sinovac.com. Other information regarding potential participants in any such proxy solicitation will

be filed by SINOVAC.

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, including the Company's

statements related to the Compliance Plan, and timing and actions taken to regain compliance with Nasdaq listing rules. Such statements

are based upon the Company's current expectations and current market and operating conditions and relate to events that involve

known or unknown risks, uncertainties and other factors, including without limitation risks, uncertainties and factors related to the

timing of engaging independent auditors and completion of the audits of required fiscal periods, completion and filing of the 2024 Annual

Report, the Compliance Plan, and actions taken to regain compliance with the Nasdaq listing rules, all of which are difficult to predict

and many of which are beyond the Company's control, which may cause the Company's 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 does not undertake

any obligation to update any forward-looking statement as a result of new information, future events or otherwise, except as required