Details Why Change is Needed on Sinovac's Board in Order to Restore Company's Previous Success and Reverse Value-Destructive Path Taken Under Current Board

Affirms Commitment to Seeing Company Reinstate Trading on the NASDAQ, Fairly Issue Dividends and Overhaul Corporate Governance

Encourages Shareholders to Support Slate of Director Nominees Proposed by SAIF for Election at Upcoming July 8 Special Meeting

For More Information, Visit www.SaveSinovac.com

Prime Success L.P., (together with its affiliates, "Prime Success" or "we"), a significant shareholder of Sinovac Biotech Ltd. (NASDAQ:SVA) ("Sinovac" or the "Company") with ownership of approximately 8% of the Company's outstanding shares, today issued a letter to shareholders in connection with the upcoming Special Meeting of Shareholders (the "Special Meeting") scheduled for July 8, 2025.

This press release features multimedia. View the full release here: https://www.businesswire.com/news/home/20250610033915/en/

The full text of the letter can be viewed here and by visiting www.SaveSinovac.com.

In its letter, Prime Success outlines the need for change on Sinovac's Board of Directors (the "Board") and presents key reasons to support the election of SAIF Partners IV L.P.'s ("SAIF") nominees, who are committed to taking the following value-enhancing actions:

Oversee a fair, equitable, and timely distribution of cash dividends, including fully supporting the payment of the announced dividend of approximately $55 per share to all shareholders, but also actively advocating for the distribution of future dividends from the subsidiaries. Prime Success wants to ensure that the value accumulated in the Company under the management team's leadership over the years is rightfully returned to all shareholders in a timely manner.
Reinstate normal trading of the Company's shares on NASDAQ and stabilize operations by resolving the uncertainty created by the current Board and taking steps to put the external auditor back on track.
Overhaul governance and rebuild investor trust by adhering to corporate governance best practices, promoting greater transparency and enhancing board accountability.
Lay the groundwork for sustainable long-term growth by leveraging the candidates' independence, backgrounds, and expertise to support the Company's continued development and expansion.

Prime Success contrasts this with the current Sinovac Board members, who have:

Taken actions leading to and prolonging the 2019 NASDAQ halt of trading in the Company's shares, significantly harming Sinovac's growth.
Impeded the Company's ability to issue dividends over the past seven years through prolonged litigation stemming from 1Globe Capital LLC's ("1Globe") undisclosed efforts to seize board control, causing significant shareholder harm.
Wasted Company resources on multiple lawsuits across various forums at the broader shareholder base's expense.
Weaponized Sinovac's allocation of capital as part of their attempt to invalidate the shares of long-term investors by attempting an unjust and potentially unlawful scheme of dividend distribution.
Prioritized personal interests over fiduciary obligations to all shareholders by seeking to void the Company's contractual obligations to benefit current Board members.
Created significant operational uncertainty by attempting to invalidate the decisions made by the prior Board that directly led to the Company's tremendous global commercial success in the past few years, resulting in the resignation of Sinovac's external auditor.
Alienated management to such a significant degree that the Sinovac management team issued an unprecedented public statement calling for a new Board election.¹
Appointed directors with flawed ethics through questionable and potentially unlawful procedures, resulting in disproportionate representation of investors and eroding shareholder trust.

Prime Success shares its belief that supporting SAIF's slate is essential for the future success of Sinovac and encourages shareholders to wait for and read SAIF's proxy materials before voting for the Special Meeting on July 8, 2025.

About Prime Success, L.P.

Prime Success is an investment vehicle established by Advantech Capital specifically to invest in Sinovac and Sinovac Life Sciences; Advantech Capital is a private equity fund established in 2016 with a focus on innovation-driven growth opportunities in China.

____________________________________

¹ Press Release: SINOVAC Management Statement Regarding Auditor Resignation (April 22, 2025)

View source version on businesswire.com: https://www.businesswire.com/news/home/20250610033915/en/

Media Contact

Longacre Square Partners

Dan Zacchei / Miller Winston

advantech@longacresquare.com

Prime Success Sends Letter to Sinovac Biotech Shareholders