[None (Title of Class) Indicate the number of outstanding shares of each of the issuer’s classes of capital or common stock as of the close of the period covered by the annual report. 55,091,561 common shares as of December 31, 2012 o Yes x No o Yes x No x Yes o No x Yes o No Large accelerated filer] [SINOVAC BIOTECH LTD. ARTICLE 1. PURPOSE Plan Company The purpose of the Sinovac Biotech Ltd. 2012 Share Incentive Plan (the “ ARTICLE 2. DEFINITIONS AND CONSTRUCTION Wherever the following terms are used in the Plan they shall have the meanings specified below, unless the context clearly indicates otherwise. The singular pronoun shall include the plural where the context so indicates.] [SUPPLEMENTAL AGREEMENT TO A LEASE CONTRACT Party A Lessor: China Bioway Biotech Group Co., Ltd. (hereinafter referred to as “ Party B Lessee: Sinovac Biotech Co., Ltd. (hereinafter referred to as “ Original Lease Contract WHEREAS, Party A and Party B signed a lease contract on August 12, 2004, under which Party A leased its No.2 Factory located in the] [SUPPLEMENTAL AGREEMENT TO A LEASE CONTRACT Party A Lessor: China Bioway Biotech Group Co., Ltd. (hereinafter referred to as “ Party B Lessee: Sinovac Biotech Co., Ltd. (hereinafter referred to as “ Original Lease Contract WHEREAS, Party A and Party B signed a lease contract on June 4, 2007, under which Party A leased its No.1 Factory located in the] [SUPPLEMENTAL AGREEMENT TO A LEASE CONTRACT Lessor Party A: China Bioway Biotech Group Co., Ltd. (the “ Original Lessee Party B: Sinovac Biotech Co., Ltd. (the “ New Lessee Party C: Beijing Sinovac R&D Technology Co., Ltd. (the “ Original Contract Based on the principles of equality and mutual benefit, Party A, Party B and Party C hereby enter into] [SUPPLEMENTAL AGREEMENT TO A LEASE CONTRACT Party A Lessor: China Bioway Biotech Group Co., Ltd. (hereinafter referred to as “ Party B Lessee: Beijing Sinovac R&D Technology Co., Ltd. (hereinafter referred to as “ Sinovac Beijing Original Lease Contract WHEREAS, Party A, Party B and Sinovac Biotech Co., Ltd. (hereinafter referred to as “ 1. Both parties agree that the] [List of Subsidiaries 1. Sinovac Biotech (Hong Kong) Ltd., a Hong Kong company 2. Tangshan Yian Biological Engineering Co., Ltd., a PRC company 3. Sinovac Biotech Co., Ltd., a PRC company 4. Sinovac Research and Development Co., Ltd. (formerly known as Beijing Sinovac Biological Technology Co., Ltd.), a PRC company 5. Sinovac (Dalian) Vaccine Technology Co., Ltd., a PRC company] [Certification by the Chief Executive Officer I, Weidong Yin, certify that: 1. I have reviewed this annual report on Form 20-F of Sinovac Biotech Ltd. (the “Company”); 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of] [Certification by the Chief Financial Officer I, Danny Chung, certify that: 1. I have reviewed this annual report on Form 20-F of Sinovac Biotech Ltd. (the “Company”); 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of] [Certification by the Chief Executive Officer 2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. EX-13.1 10 a13-4096_1ex13d1.htm EX-13.1] [Certification by the Chief Financial Officer 2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. EX-13.2 11 a13-4096_1ex13d2.htm EX-13.2] [CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in the Registration Statement (Form S-8 No. 333-161827) pertaining to the 2003 Stock Option Plan of Sinovac Biotech Ltd., of our reports dated April 29, 2013, with respect to the consolidated financial statements of Sinovac Biotech Ltd. and the effectiveness of internal control over financial reporting]