[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. 55,570,361 common shares as of December 31, 2013 o Yes x No o Yes x No x Yes o No x Yes o No Large accelerated filer] [4.20 April 1 6 , 2014 100 F Street, N.T. Ladies and Gentlemen: We have read Item 16F of the Annual Report on Form 20-F for the year ended December 31, 2013 dated April 1 6 Vancouver, Canada EX-4.20 2 a14-4385_1ex4d20.htm EX-4.20] [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. (t he “ 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] [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] [Certification by the Chief Executive Officer In connection with the annual report of Sinovac Biotech Ltd. Weidong Yin (2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. 16 , 2014 Weidong Yin Chief Executive Officer 1 EX-13.1 6 a14-4385_1ex13d1.htm EX-13.1] [Certification by the Chief Financial Officer In connection with the annual report of Sinovac Biotech Ltd. (2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. 16 , 2014 Nan Wang Chief Financial Officer 1 EX-13.2 7 a14-4385_1ex13d2.htm EX-13.2] [Consent of Independent Registered Public Accounting Firm We consent to the incorporation by reference in the Registration Statement on Form S-8 (No.333-161827) pertaining to Sinovac Biotech Ltd.’s 2003 Stock Option Plan and the Registration Statement on Form S-8 (No.333-190980) pertaining to Sinovac Biotech Ltd.’s 2012 Share Incentive Plan of our reports dated April 16, 2014, with respect to the consolidated] [Consent of Independent Registered Public Accounting Firm We consent to the incorporation by reference in the Registration Statement onForm S-8 (No. 333-161827) pertaining Sinovac Biotech Ltd.’s 2003 Stock Option Plan and the Registration Statement on Form S-8 (No. 333-190980) pertaining to Sinovac Biotech Ltd.’s 2012 Share Incentive Plan of our report dated April 29, 2013, with respect to the consolidated]