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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 the following letter in response to the Company's recent false and misleading claims relating to the upcoming Special Meeting of Shareholders (the "Special Meeting") scheduled for July 8, 2025.

The full text of the letter is below and available at www.SaveSinovac.com.

Dear fellow Sinovac shareholders,

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"), continues to be disappointed by the current Board's ("1Globe Activist Board") distortion of the facts about what is at stake at the upcoming Special Meeting of Shareholders (the "Special Meeting") scheduled for July 8, 2025. In our June 10 letter we addressed several of the 1Globe Activist Board's misstatements and are taking the opportunity to remind all shareholders why the 1Globe Activist Board cannot be trusted:

1. Prime Success is insisting that a dividend be distributed – for all shareholders

The 1Globe Activist Board's false comments are just not credible – why would any investor be against receiving a dividend? The 1Globe Activist Board wants you to believe that Prime Success is the reason that dividends have not been distributed, but we are not the Company and are not on the Board, and dividend distribution decisions are not ours to make. We can only continue to advocate on behalf of all shareholders that they should be made.

Under the leadership of a SAIF Partners IV L.P. ("SAIF") nominated Board — composed of seasoned professionals with proven governance experience, deep operational insight, and a track record of building real, lasting value — we are confident that the pattern of internal conflict and ongoing litigation fueled by the 1Globe Activist Board can be broken, and shareholders can look forward to more future dividends. But that will not be possible with the 1Globe Activist Board in power as they have made clear they prioritize endless litigation over the Company's long-term success.

2. The 1Globe Activist Board is deliberately baiting shareholders by setting the dividend distribution date for one day after the Special Meeting. We call upon the Company to make dividend distribution before the Special Meeting

The 1Globe Activist Board deliberately set the dividend date for one day after the Special Meeting which creates the false impression that shareholders must vote for the incumbents to receive the dividends. But the upcoming Special Meeting will determine the Company's future direction and the long-term interests of all shareholders. We call on the 1Globe Activist Board to allow for a fair, pro rata distribution of dividends and to move the date of the dividend distribution to before the Special Meeting so the meeting can refocus on its proper purpose: electing a competent Board.

3. The 1Globe Activist Board distorts historic facts to aggrandize 1Globe and smear legitimate investors

Let's compare facts against rhetoric of the 1Globe Activist Board. Over the past seven years, what have we contributed to the Company?

The critical lifeline investments from Prime Success and Vivo Capital, LLC, combined with management's determined efforts, enabled Sinovac to seize a pivotal opportunity: the development of CoronaVac. This initiative ultimately resulted in the delivery of billions of doses to over 60 countries, generating substantial revenues while saving countless lives. Without the success of CoronaVac, there would not be any sizable dividend to distribute now.

In contrast, what has 1Globe done for the Company?

It has initiated multi-jurisdictional litigation against Sinovac, leading to a waste of company resources. The 1Globe Activist Board's mischaracterization of 1Globe and Prime Success' relative contribution to Sinovac and its shareholders reveals its deeply partisan nature.

4. Shareholders: looking forward, it's time to focus on what truly matters – the future of your investment in Sinovac

Sinovac needs a Board that will roll up its sleeves and run the business, guiding the Company forward on a stable, productive path. The slate put forward by SAIF, consisting of representatives from all shareholders owning more than 5% of the Company's equity stake, many of whom possess deep industry experience, achieves exactly that.

We urge all shareholders to focus on the future and choose the leadership that will best secure our Company's success in the years to come. We look forward to continuing to make our case for change to our fellow shareholders and encourage them to wait for and read SAIF's proxy materials before voting for the Special Meeting on July 8, 2025.

Sincerely,

Prime Success, L.P.

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.

View source version on businesswire.com: https://www.businesswire.com/news/home/20250613698243/en/

Media Contact

Longacre Square Partners

Dan Zacchei / Miller Winston

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Prime Success Responds to Sinovac Biotech's False and Misleading Claims