[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. 54,773,961 common shares as of December 31, 2011 Yes o No x Yes o No x Yes x No o Yes x No o Large accelerated filer] [SINOVAC BIOTECH LTD. ANTIGUA AND BARBUDA The International Business Corporations Act, 1982 No. 28 of 1982 Cap. 222 Vol. 5 of the Revised Laws of Antigua 1992 Edition A Company Limited by Shares ARTICLES OF INCORPORATION OF SINOVAC BIOTECH LTD. Amended on March 21, 2006 ARTICLE I. NAME The name of the Corporation is SINOVAC BIOTECH LTD. ARTICLE II. REGISTERED] [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, Nan Wang, 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 6 a12-6625_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 7 a12-6625_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 12, 2012, with respect to the consolidated financial statements of Sinovac Biotech Ltd. and the effectiveness of internal control over financial reporting]