Please wait



Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Checkbox not checked   Rule 13d-1(b)
Checkbox not checked   Rule 13d-1(c)
Checkbox not checked   Rule 13d-1(d)


SCHEDULE 13D/A 0001618789 XXXXXXXX LIVE 4 Common Shares, $0.001 par value per share 04/23/2025 false 0001084201 P8696W104 Sinovac Biotech Ltd. No. 39 Shangdi Xi Road Haidian District Beijing F4 100085 Vivo Capital, LLC (650) 688-0818 192 Lytton Avenue, Palo Alto CA 94301 Stephen Blake 650-251-5000 Simpson Thacher & Bartlett LLP 2475 Hanover Street, Palo Alto CA 94304 Bryan Jin 650-251-5000 Simpson Thacher & Bartlett LLP 2475 Hanover Street, Palo Alto CA 94304 0001618789 N Vivo Capital VIII, LLC b WC N DE 0.00 1360544.00 0.00 1360544.00 1360544.00 N 1.9 OO The beneficial ownership reported herein reflects that 1,195,465 of such shares are held by Vivo Capital Fund VIII, L.P. and 165,079 of such shares are held by Vivo Capital Surplus Fund VIII, L.P. Vivo Capital VIII, LLC is the general partner of both Vivo Capital Fund VIII, L.P. and Vivo Capital Surplus Fund VIII, L.P. The beneficial ownership percentage reported herein is based on 71,860,702 common shares outstanding as of March 31, 2024, as reported in the Issuer's Form 20-F filed with the Securities and Exchange Commission on April 29, 2024. 0001750698 N Vivo Capital IX, LLC b WC N DE 0.00 4539456.00 0.00 4539456.00 4539456.00 N 6.3 OO The beneficial ownership reported herein reflects that such shares are held by Vivo Capital Fund IX, L.P. Vivo Capital IX, LLC is the general partner of Vivo Capital Fund IX, L.P. The beneficial ownership percentage reported herein is based 71,860,702 common shares outstanding as of March 31, 2024, as reported in the Issuer's Form 20-F filed with the Securities and Exchange Commission on April 29, 2024. Common Shares, $0.001 par value per share Sinovac Biotech Ltd. No. 39 Shangdi Xi Road Haidian District Beijing F4 100085 Reference is hereby made to the statement on Schedule 13D filed with the Securities and Exchange Commission on July 11, 2018 by Vivo Capital, LLC with respect to the Common Shares, par value $0.001 per share ("Common Shares") of Sinovac Biotech Ltd. (the "Issuer"), Amendment No. 1 thereto filed by Vivo Capital, LLC and Vivo Capital VIII, LLC on July 20, 2018, Amendment No. 2 thereto filed by Vivo Capital, LLC, Vivo Capital VIII, LLC and Vivo Capital IX, LLC on August 27, 2018 and Amendment No. 3 thereto filed by Vivo Capital VIII, LLC and Vivo Capital IX, LLC on March 19, 2025 (as so amended, the "Schedule 13D"). The Items herein amend the information disclosed under the corresponding Items of the Schedule 13D as described herein. Capitalized terms used herein and not otherwise defined have the meanings ascribed to them in the Schedule 13D. Item 4 is hereby supplemented and amended by adding the following: On April 23, 2025, Vivo Capital LLC, an affiliate of the Reporting Persons, issued a press release announcing multiple legal proceedings in response to the Issuer's New Board's certain recent actions that have destabilized the Issuer and precipitated a corporate governance crisis. The press release is attached hereto as Exhibit I and incorporated herein by reference. The Reporting Persons, and their affiliates, anticipate taking additional legal actions as needed to further protect their rights. Item 6 is hereby supplemented and amended by adding the following: Item 6 of the Schedule 13D is hereby supplemented and amended to incorporate by reference the information set forth in Item 4 to this Amendment No. 4 to Schedule 13D. Item 7 is hereby supplemented and amended by adding the following: Exhibit No. Description 1 Press Release dated April 23, 2025* * Filed herewith Vivo Capital VIII, LLC /s/ Dr. Frank Kung Dr. Frank Kung, Managing Member 04/24/2025 Vivo Capital IX, LLC /s/ Dr. Frank Kung Dr. Frank Kung, Managing Member 04/24/2025