Sinovac Biotech (SVA) holder SAIF revises share sale and put option rights

Rhea-AI Filing Summary

Sinovac Biotech’s major shareholder SAIF Partners IV and its affiliated entities report continued beneficial ownership of 10,780,820 common shares, representing 15% of the company’s common shares, based on 71,860,702 shares outstanding as of March 31, 2024.

On December 15, 2025, SAIF Partners IV L.P. (the Seller) and YZ Healthcare L.P. (the Buyer) entered into an Amended and Restated Investment Agreement. The revisions extend the Buyer’s right of first refusal period for secondary sales by SAIF and limit the shares covered by that right to an amount equal in value to the Buyer’s deposit under the prior agreement. The amendment also extends the time during which SAIF may exercise a put option to sell designated shares to the Buyer, tied to whether a share purchase agreement is signed before the new right of first refusal period expires.

Insights

Equity ownership and governance analyst

SAIF keeps a 15% Sinovac stake while renegotiating its exit mechanics with YZ Healthcare.

SAIF Partners IV and its general partners report beneficial ownership of 10,780,820 common shares, or 15% of Sinovac’s equity, calculated against 71,860,702 shares outstanding as of March 31, 2024. This confirms SAIF’s role as a significant shareholder rather than signaling a new acquisition or disposal.

The Amended and Restated Investment Agreement dated December 15, 2025 between SAIF Partners IV L.P. and YZ Healthcare L.P. revises secondary sale mechanics. It extends the Buyer’s right of first refusal window and caps covered shares at an aggregate price equal to the Buyer’s deposit under the prior agreement.

The amendment also lengthens when SAIF can use its put option on the “Put Option Shares,” either before closing of any share purchase agreement signed within the right of first refusal period or within 15 business days after that period expires if no agreement is signed. Overall, this filing refines exit rights between existing holders without describing new share issuance by Sinovac.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 20)

SINOVAC BIOTECH LTD.

(Name of Issuer)

Common Shares, par value US$0.001 per share

(Title of Class of Securities)

P8696W104

(CUSIP Number)

Andrew Y Yan
c/o Suite 1102, Five Pacific Place, 28 Hennessy Road, Wanchai
Hong Kong, K3, 00000
852-2918-2200

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

12/15/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. P8696W104

1

Name of reporting person

SAIF Partners IV L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 10,780,820.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 10,780,820.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

10,780,820.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

15.00 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

Comments to item 13: Calculation is based on 71,860,702 Common Shares of the Issuer outstanding as of March 31, 2024 according to the Issuer's annual report on Form 20-F for the fiscal year ended December 31, 2023 (the "2023 Annual Report").

SCHEDULE 13D

CUSIP No. P8696W104

1

Name of reporting person

SAIF IV GP, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 10,780,820.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 10,780,820.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

10,780,820.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

15.00 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

Comments to item 13: Calculation is based on 71,860,702 Common Shares of the Issuer outstanding as of March 31, 2024 according to the 2023 Annual Report.

SCHEDULE 13D

CUSIP No. P8696W104

1

Name of reporting person

SAIF IV GP Capital Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 10,780,820.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 10,780,820.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

10,780,820.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

15.00 %

14

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person:

Comments to item 13: Calculation is based on 71,860,702 Common Shares of the Issuer outstanding as of March 31, 2024 according to the 2023 Annual Report.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Shares, par value US$0.001 per share
(b)	Name of Issuer: SINOVAC BIOTECH LTD.
(c)	Address of Issuer's Principal Executive Offices: No. 39 Shangdi Xi Rd, Haidian District, Beijing, CHINA , 100085.
Item 1 Comment: This Amendment No.20 to Schedule 13D is being filed on behalf of each of SAIF Partners IV L.P., SAIF IV GP, L.P., and SAIF IV GP Capital Ltd. (each, a "Reporting Person," and collectively, the "Reporting Persons"), to amend the Schedule 13D relating to the common shares, par value $0.001 per share (the "Common Shares"), of Sinovac Biotech Ltd. (the "Issuer"), filed by the Reporting Persons on May 31, 2011, as amended by Amendment No.1 to Schedule 13D filed on August 23, 2011, Amendment No.2 to Schedule 13D filed on September 30, 2011, Amendment No.3 to Schedule 13D filed on November 29, 2011, Amendment No.4 to Schedule 13D filed on December 30, 2011, Amendment No.5 to Schedule 13D filed on February 2, 2016, Amendment No. 6 to Schedule 13D filed on June 26, 2017, Amendment No. 7 to Schedule 13D filed on December 12, 2022, Amendment No. 8 to Schedule 13D filed on March 15, 2023, Amendment No. 9 to Schedule 13D filed on May 25, 2023, Amendment No. 10 to Schedule 13D filed on September 15, 2023, Amendment No. 11 to Schedule 13D filed on December 1, 2023, Amendment No. 12 to Schedule 13D filed on June 17, 2024, and Amendment No. 13 to Schedule 13D filed on September 12, 2024, Amendment No. 14 to Schedule 13D filed on February 19, 2025, Amendment No. 15 to Schedule 13D filed on March 19, 2025, Amendment No. 16 to Schedule 13D filed on April 28, 2025, Amendment No. 17 to Schedule 13D filed on May 23, 2025, Amendment No. 18 to Schedule 13D filed on June 17, 2025, and Amendment No. 19 to Schedule 13D filed on July 14, 2025 (collectively, the "Original Schedule 13D"). The information in each Item below amends the information disclosed under the corresponding Item of the Original Schedule 13D. Except as amended and supplemented in previous amendments and herein, the information set forth in the Original Schedule 13D remains unchanged. Capitalized terms used herein have meanings as assigned thereto in the Original Schedule 13D unless defined herein. The information set forth in response to each separate Item below shall be deemed to be a response to all Items where such information is relevant.
Item 6.	Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer
	Item 6 is hereby amended and supplemented as follows: On December 15, 2025, the Seller and the Buyer entered into an Amended and Restated Investment Agreement (the "A&R Investment Agreement") to amend and restate that certain Investment Agreement dated November 23, 2022 (as amended, the "Prior Agreement"), which changes include, among others, extending the period of the Buyer's right of first refusal period ("ROFR Period"), during which the Buyer has a right to elect to purchase all of the shares of the Issuer that the Seller would sell to any person (other than (i) any of its affiliate or an existing limited partner or (ii) any sale on public markets or over the counter) at the same price and subject to the same material terms and conditions proposed by such person set forth on the Transfer Notice (as defined below), to the date which is the 5th business day following the Seller's delivery of a written notice notifying its intention of such proposed sale (the "Transfer Notice"), and limiting the number of shares subject to the Buyer's right of first refusal to such number of the shares that has an aggregate consideration equal to the deposit amount paid by the Buyer to the Seller pursuant to the Prior Agreement. As a result of this extension of the ROFR Period, the period during which the Buyer may exercise the Put Option is also extended in the following manner: (i) if the Buyer and the Seller enter into a share purchase agreement with respect to any shares of the Issuer prior to the expiration of the ROFR Period, the Seller may exercise the Put Option prior to the closing of the sales under such share purchase agreement to sell the Put Option Shares to the Buyer; and (ii) if no such share purchase agreement is executed prior to the expiration of the ROFR Period, the Seller may exercise the Put Option within 15 business days immediately following the expiry of the ROFR Period to sell the Put Option Shares to the Buyer. References to each of the Prior Agreement and all the amendments thereto in this Statement are qualified in their entirety by reference to the full text of the Prior Agreement and all of the amendments thereto, which are attached hereto as exhibits or incorporated herein by reference as if set forth in their entirety herein. Reference to the A&R Investment Agreement in this Statement is qualified in its entirety by reference to the full text of the A&R Investment Agreement, which is attached hereto as an exhibit or incorporated herein by reference as if set forth in its entirety herein.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 7.01 Joint Filing Agreement by and among SAIF Partners IV L.P., SAIF IV GP L.P. and SAIF IV GP Capital Ltd., dated as of June 27, 2017. Exhibit 7.02 Investment Agreement dated November 23, 2022 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.03 Amendment No.1 to Investment Agreement dated March 15, 2023 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.04 Amendment No.2 to Investment Agreement dated May 25, 2023 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.05 Amendment No.3 to Investment Agreement dated September 15, 2023 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.06 Amendment No.4 to Investment Agreement dated December 1, 2023 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.07 Amendment No.5 to Investment Agreement dated June 13, 2024 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.08 Amendment No.6 to Investment Agreement dated September 12, 2024 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.09 Amendment No.7 to Investment Agreement dated February 18, 2025 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.10 Amendment No.8 to Investment Agreement dated May 23, 2025 between SAIF Partner IV L.P. and YZ Healthcare L.P. Exhibit 7.11 Amended and Restated Investment Agreement dated December 15, 2025 between SAIF Partner IV L.P. and YZ Healthcare L.P.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

SAIF Partners IV L.P.

Signature:	/s/Andrew Y Yan
Name/Title:	Director of SAIF IV GP Capital Ltd., which is the General Partner of SAIF IV GP, L.P., which is the General Partner of SAIF Partners IV L.P.
Date:	12/17/2025

SAIF IV GP, L.P.

Signature:	/s/Andrew Y Yan
Name/Title:	Director of SAIF IV GP Capital Ltd., which is the General Partner of SAIF IV GP, L.P.
Date:	12/17/2025

SAIF IV GP Capital Ltd.

Signature:	/s/Andrew Y Yan
Name/Title:	Director of SAIF IV GP Capital Ltd.
Date:	12/17/2025

FAQ

How many Sinovac (SVA) shares does SAIF Partners IV currently beneficially own?

SAIF Partners IV and its affiliated reporting entities beneficially own 10,780,820 Sinovac common shares. This represents 15% of the company’s outstanding common shares, based on 71,860,702 shares outstanding as of March 31, 2024, according to Sinovac’s 2023 annual report.

What percentage of Sinovac (SVA) does SAIF Partners IV’s stake represent?

SAIF Partners IV’s reported stake represents 15% of Sinovac’s common shares. The percentage is calculated using 71,860,702 common shares outstanding as of March 31, 2024, as disclosed in Sinovac’s Form 20-F for the year ended December 31, 2023.

What is the Amended and Restated Investment Agreement between SAIF Partners IV and YZ Healthcare?

The Amended and Restated Investment Agreement dated December 15, 2025, updates a 2022 investment agreement between SAIF Partners IV L.P. and YZ Healthcare L.P.. It revises the Buyer’s right of first refusal and put option terms relating to potential secondary sales of Sinovac shares held by SAIF.

How did the right of first refusal change for Sinovac (SVA) shares under this amendment?

The amendment extends the Buyer’s right of first refusal period to the fifth business day after SAIF delivers a transfer notice. It also limits covered shares to the number whose aggregate sale price equals the deposit amount YZ Healthcare previously paid to SAIF under the prior agreement.

How was the put option period on Sinovac (SVA) shares adjusted for SAIF Partners IV?

The put option period now depends on whether a share purchase agreement is signed within the right of first refusal period. SAIF can exercise the put option either before closing such an agreement or within 15 business days after the right of first refusal expires if no agreement is executed.

Does this amendment involve Sinovac (SVA) issuing new shares?

The disclosed changes concern secondary share transfers between SAIF Partners IV (the Seller) and YZ Healthcare (the Buyer). The terms describe rights over existing Sinovac shares held by SAIF and do not state that Sinovac itself is issuing any new shares in this arrangement.