6-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of April 2019

--------------

Commission File Number: 001-32371

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SINOVAC BIOTECH LTD.

No. 15 Zhi Tong Road

Zhongguancun Science and Technology Park

Changping District

Beijing 102200, People’s Republic of China

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F x Form 40-F ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):________________

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):________________

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

SINOVAC BIOTECH LTD.
By:	/s/ Nan Wang
Name:	Nan Wang
Title:	Chief Financial Officer

Date: April 29, 2019

Exhibit Index

Exhibit 99.1 Press Release

EX-99.1

Exhibit 99.1

Sinovac Reports Unaudited Second Half of 2018 Financial Results and Files 2018 Annual Report on Form 20-F

BEIJING, China, April 29, 2019 /PRNewswire/ -- Sinovac Biotech Ltd. (NASDAQ: SVA) (“Sinovac” or the “Company”), a leading provider of biopharmaceutical products in China, has filed its 2018 annual report on Form 20-F with the U.S. Securities and Exchange Commission for the year ended December 31, 2018. The Company also reported its unaudited financial results for the second half of the year ended December 31, 2018.

Second Half of 2018 Financial Highlights

Ÿ Sales for the second half of 2018 were $107.2 million, which remains the same compared to $107.4 million in the prior year period. Revenue generated by Hepatitis A vaccine increased by $12.0 million compared to same period in 2017, which was offset by $13.6 million decrease in the Company’s influenza vaccine. In second half of 2018, nil revenue generated by the Company’s influenza vaccine in the flu season 2018-2019 caused by the suspension of influenza vaccine production and destruction of inventory in April 2018 as a result of the disruptive actions of the minority shareholder of our subsidiary, Sinovac Biotech Co., Ltd.

Ÿ Net income attributable to common shareholders was $7.7 million, or $0.11 per basic and diluted share, compared to net income attributable to common shareholders of $15.0 million, or $0.26 per basic and diluted share, in the prior year period.

Full Year 2018 Financial Highlights

Ÿ Sales in 2018 were $229.7 million, an increase of 31.7% from $174.3 million in 2017. Sales increased primarily due to revenue generated by the Company’s EV71 vaccine.

Ÿ Net income attributable to common shareholders was $21.8 million, or $0.34 per basic and diluted share in 2018, compared to net income attributable to common shareholders of $25.8 million, or $0.45 per basic and diluted share in 2017.

Business Highlights

Marketing and Sales

The overall vaccine market in China grew in 2018 despite serious impacts from the Changchun vaccine scandal. In addition, although there was no seasonal flu vaccine supply in 2018 due to the production suspension, total sales of the Company’s regular products increased by 31.7% year over year.

Research and Development

Varicella – Human clinical studies have been completed. The new drug application (NDA) was filed with the National Medical Products Administration (NMPA, previously known as the China State Food and Drug Administration) in November 2017. The clinical site inspection was completed in 2018. The technical review on the registration dossier was also conducted in 2018 and supplementary documents were issued and responded to during the year.

Sabin Inactivated Polio Vaccine (sIPV) – The Company has completed phase III clinical studies, which found that the immune responses against the three types of poliovirus in the studied sIPV were not inferior to those achieved with the control IPV and demonstrated a good safety profile. A sequential study of inoculation with bivalent oral polio vaccine (bOPV) was completed in 2018. In January 2019, the NDA was submitted to the NMPA. The consistency study on three consecutive lots is expected to start in 2019.

23 Valent Pneumococcal Polysaccharide Vaccine – The Company filed an NDA in June 2017. The clinical trial site inspection has been completed, and a registration dossier is being reviewed by the NMPA. The technical review on the registration dossier was conducted in 2018 and supplementary documents were issued and responded to during the year.

Quadrivalent Influenza Vaccine (QIV) – Phase III trial has been completed. The preliminary results of the trial show that the vaccine is safe and immunogenic. The NDA has been filed, and the application is under review by the NMPA.

Unaudited Financial Results for Second Half of 2018

Summary of sales and gross profit

(In $000 except percentage data)	2018 2H			% of Sales			2017 2H		% of Sales
Hepatitis A – Healive		26,567			24.8	%		14,542		13.5	%
Hepatitis A&B – Bilive		662			0.6	%		5,502		5.2	%
Hepatitis vaccines subtotal		27,229			25.4	%		20,044		18.7	%
Influenza vaccine		(35	)		0.0	%		13,550		12.6	%
Enterovirus 71 vaccine		78,424			73.2	%		72,533		67.5	%
Mumps vaccine		1,542			1.4	%		1,311		1.2	%
Total sales		107,160			100.0	%		107,438		100.0	%
Cost of sales		11,386			10.6	%		12,505		11.6	%
Gross profit		95,774			89.4	%		94,933		88.4	%

2

Sales for the second half of 2018 were $107.2 million, which remains the same compared to $107.4 million in the prior year period. Revenue generated by Hepatitis A vaccine increased by $12.0 million compared to same period in 2017, which was offset by $13.6 million decrease in the Company’s influenza vaccine. In second half of 2018, nil revenue generated by the Company’s influenza vaccine in the flu season 2018-2019 caused by the suspension of influenza vaccine production and destruction of inventory in April 2018 as a result of the disruptive actions of the minority shareholder of our subsidiary, Sinovac Biotech Co., Ltd.

Gross profit was $95.8 million compared to gross profit of $94.9 million in the prior year period. Gross margin was 89.4% compared to 88.4% in the prior year period. Gross profit in the second half of 2018 increased slightly due to a change in sales mix, with a greater proportion of sales generated by the Company’s higher-margin EV71 vaccine.

Selling, general and administrative expenses in the second half of 2018 were $69.2 million compared to $50.6 million in the same period of 2017. The increase was mainly due to higher professional and consulting fees associated with ongoing litigation.

R&D expenses in the second half of 2018 were $11.8 million compared to $11.7 million in the same period of 2017.

Net income in the second half of 2018 was $13.5 million compared to $20.9 million in the prior year period.

Net income attributable to common shareholders was $7.7 million, or $0.11 per basic and diluted share, compared to net income attributable to common shareholders of $15.0 million, or $0.26 per basic and diluted share, in the prior year period.

Non-GAAP adjusted EBITDA was $20.6 million in the second half of 2018 compared to $35.4 million in the prior year period. Non-GAAP net income in the second half of 2018 was $15.9 million compared to $20.2 million in the prior year period. Non-GAAP diluted earnings per share in the second half of 2018 were $0.13 compared to $0.25 per share in the prior year period. Reconciliations of non-GAAP measures to the nearest comparable GAAP measures are included at the end of this earnings announcement.

3

Financial Results for the Twelve Months Ended December 31, 2018

Summary of sales and gross profit

(In $000 except percentage data)	2018		% of Sales			2017		% of Sales
Hepatitis A – Healive		52,420		22.8	%		27,421		15.7	%
Hepatitis A&B – Bilive		11,006		4.8	%		10,430		6.0	%
Hepatitis vaccines subtotal		63,426		27.6	%		37,851		21.7	%
Influenza vaccine		2,028		0.9	%		13,544		7.7	%
Enterovirus 71 vaccine		162,537		70.8	%		121,284		69.6	%
Mumps vaccine		1,659		0.7	%		1,667		1.0	%
Total sales		229,650		100.0	%		174,346		100.0	%
Cost of sales		24,723		10.8	%		20,240		11.6	%
Gross profit		204,927		89.2	%		154,106		88.4	%

Sales in 2018 were $229.7 million, an increase of 31.7% from $174.3 million in 2017. Sales increased primarily due to revenue generated by the Company’s EV71 and hepatitis vaccines.

Gross profit in 2018 was $204.9 million, an increase of 33.0% from $154.1 million in 2017. Gross margin was 89.2% compared to 88.4% in 2017. Gross profit in 2018 also increased primarily due to higher sales generated by the Company’s EV71 vaccine.

Selling, general and administrative expenses in 2018 were $137.0 million compared to $87.4 million in 2017. The Company’s selling, general and administrative expenses increased with the higher level of sales activity. The Company incurred $11.4 million in professional and consulting fees associated with ongoing litigation.

R&D expenses in 2018 were $21.9 million compared to $20.5 million in 2017. R&D expenses were mainly incurred by the development of varicella vaccine and sIPV.

Net income was $36.1 million in 2018 compared to net income of $36.7 million in 2017.

Net income attributable to common shareholders was $21.8 million, or $0.34 per basic and diluted share in 2017, compared to net income attributable to common shareholders of $25.8 million, or $0.45 per basic and diluted share in 2017.

Non-GAAP adjusted EBITDA was $54.8 million in 2018 compared to $51.3 million in 2017. Non-GAAP net income in 2018 was $39.9 million compared to net income of $36.4 million in 2017. Non-GAAP diluted earnings per share in 2018 were $0.38 compared to diluted earnings per share of $0.44 in 2017. Reconciliations of non-GAAP measures to the nearest comparable GAAP measures are included at the end of this earnings announcement.

4

As of December 31, 2018, cash and cash equivalents and restricted cash totaled $158.2 million compared to $116.0 million as of December 31, 2017. In 2018, net cash provided by operating activities was $7.9 million. Net cash used in investing activities was $25.3 million, which was primarily due to the purchase of short-term investments. Net cash provided by financing activities was $64.2 million, including loan proceeds of $18.9 million and loan repayment of $43.9 million. As of December 31, 2018, the Company had $3.3 million of bank loans due within one year. The Company expects that its current cash position will be able to support its operations for at least the next 12 months.

About Sinovac

Sinovac Biotech Ltd. is a China-based biopharmaceutical Company that focuses on the research, development, manufacturing and commercialization of vaccines that protect against human infectious diseases. Sinovac's product portfolio includes vaccines against enterovirus71, or EV71, hepatitis A and B, seasonal influenza, H5N1 pandemic influenza (avian flu), H1N1 influenza (swine flu), and mumps. Healive, the hepatitis A vaccine manufactured by the Company has passed the assessment under WHO Prequalification procedures in 2017. The EV71 vaccine, an innovative vaccine developed by Sinovac against hand foot and mouth disease caused by EV71, was commercialized in China in 2016. In 2009, Sinovac was the first company worldwide to receive approval for its H1N1 influenza vaccine, which it has supplied to the Chinese Government's vaccination campaign and stockpiling program. The Company is also the only supplier of the H5N1 pandemic influenza vaccine to the government stockpiling program. The Company is developing a number of new products including a Sabin-strain inactivated polio vaccine, pneumococcal polysaccharides vaccine, pneumococcal conjugate vaccine and varicella vaccine. Sinovac primarily sells its vaccines in China, while also exploring growth opportunities in international markets. The Company has exported select vaccines to over 10 countries in Asia and South America. For more information please see the Company’s website at www.sinovacbio.com.

Safe Harbor Statement

This press release contains “forward-looking statements” within the meaning of the United States federal securities laws. Such statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to differ materially from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements. Factors that might cause such a difference include our inability to compete successfully in the competitive and rapidly changing marketplace in which we operate, failure to retain key employees, cancellation or delay of projects, failure to satisfy regulatory and other requirements, disapproval or delay in approval of new products by regulatory bodies, disruptions to our operations, the results of any pending litigation, potential litigation relating to our shareholder rights plan, any halt in trading of the Company’s securities, and adverse general economic conditions in China, the United States and elsewhere. These risks and other factors include those listed under “Risk Factors” and elsewhere in our Annual Report on Form 20-F as filed with the Securities and Exchange Commission. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “expects,” “intends,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” “continue,” or the negative of these terms or other comparable terminology. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of activity, performance or achievements. The Company assumes no obligation to update the forward-looking information contained in this release.

5

Non-GAAP Financial Measures

To supplement its consolidated financial statements, which are prepared and presented in accordance with GAAP, Sinovac uses the following non-GAAP financial measures: non-GAAP adjusted EBITDA, non-GAAP net income and non-GAAP diluted EPS.  For more information on these non-GAAP financial measures, please refer to the table captioned “Reconciliations of non-GAAP Measures to the Nearest Comparable GAAP Measures” in this results announcement.

Sinovac believes that non-GAAP adjusted EBITDA, non-GAAP net income and non-GAAP diluted EPS help identify underlying trends in its business that could otherwise be distorted by the effect of certain income or expenses that Sinovac includes net income and diluted EPS. Sinovac believes that non-GAAP adjusted EBITDA, non-GAAP net income and non-GAAP diluted EPS provide useful information about its core operating results, enhance the overall understanding of its past performance and future prospects and allow for greater visibility with respect to key metrics used by our management in its financial and operational decision-making. Non-GAAP adjusted EBITDA, non-GAAP net income and non-GAAP diluted EPS should not be considered in isolation or construed as an alternative to income from operations, net income, diluted EPS, or any other measure of performance or as an indicator of Sinovac’s operating performance. These non-GAAP financial measures presented here may not be comparable to similarly titled measures presented by other companies.  Other companies may calculate similarly titled measures differently, limiting their usefulness as comparative measures to our data.

Non-GAAP adjusted EBITDA represents net income and excludes interest and financing expenses, interest income, net other income (expenses) and income tax benefit (expenses), and certain non-cash expenses, consisting of share-based compensation expenses, amortization and depreciation that Sinovac does not believe are reflective of the core operating performance during the periods presented.

Non-GAAP net income represents net income before share-based compensation expenses, and foreign exchange gain or loss.

Non-GAAP diluted EPS represents non-GAAP net income attributable to common shareholders divided by the weighted average number of shares outstanding during the periods on a diluted basis, including accounting for the effect of the assumed conversion of options.

Contact

Sinovac Biotech Ltd.

Helen Yang

Tel: +86-10-8279-9871

Fax: +86-10-6296-6910

Email: ir@sinovac.com

ICR Inc.

Bill Zima

U.S: 1-646-308-1707

Email: william.zima@icrinc.com

6

SINOVAC BIOTECH LTD.

Consolidated Balance sheets

As of December 31, 2018 and December 31, 2017

(Expressed in thousands of U.S. Dollars)

	December 31, 2018			December 31, 2017
Current assets
Cash and cash equivalents	$	158,170		$	114,415
Short-term investment		18,908			-
Restricted cash		-			1,549
Accounts receivable - net		74,464			66,205
Income tax receivable		2,999			-
Inventories		25,091			19,618
Prepaid expenses and deposits		4,543			2,101
Total current assets		284,175			203,888
Property, plant and equipment - net		70,920			76,430
Prepaid land lease payments		8,304			9,028
Long-term inventories		90			-
Long-term prepaid expenses to a related party		23			25
Prepayment for acquisition of equipment		470			528
Deferred tax assets		5,798			9,320
Total assets		369,780			299,219
Current liabilities
Short-term bank loans		3,321			18,152
Accounts payable and accrued liabilities		49,991			59,418
Income tax payable		-			8,862
Deferred revenue		2,907			4,073
Deferred government grants		1,986			2,038
Total current liabilities		58,205			92,543
Deferred government grants		5,961			4,474
Long-term bank loans		3,890			14,849
Deferred revenue		90			-
Loan from a non-controlling shareholder		6,705			7,070
Other non-current liabilities		3,001			3,143
Total long-term liabilities		19,647			29,536
Total liabilities		77,852			122,079
Commitments and contingencies
Equity
Preferred stock		-			-
Common stock		71			57
Additional paid-in capital		204,998			115,339
Accumulated other comprehensive income (loss)		(2,099	)		7,075
Statutory surplus reserves		26,643			19,549
Accumulated earnings		23,820			9,132
Total shareholders' equity		253,433			151,152
Non-controlling interests		38,495			25,988
Total equity		291,928			177,140
Total liabilities and equity	$	369,780		$	299,219

SINOVAC BIOTECH LTD.

Consolidated Statements of Comprehensive Income

For the six months and twelve months ended December 31, 2018 and 2017

(Expressed in thousands of U.S. Dollars, except for numbers of shares and per share data)

	Six months ended December 31						Twelve months ended December 31
	2018			2017			2018			2017
	(Unaudited)			(Unaudited)
Sales	$	107,160		$	107,438		$	229,650		$	174,346
Cost of sales		11,386			12,505			24,723			20,240
Gross profit		95,774			94,933			204,927			154,106
Selling, general and administrative expenses		69,177			50,646			137,003			87,365
Provision (recovery) for doubtful accounts		(1,756	)		407			820			934
Research and development expenses		11,836			11,710			21,910			20,489
Loss on disposal and impairment of property, plant and equipment		57			29			75			42
Government grants recognized in income		(150	)		(137	)		(197	)		(141	)
Total operating expenses		79,164			62,655			159,611			108,689
Operating income		16,610			32,278			45,316			45,417
Interest and financing expenses		(420	)		(747	)		(1,070	)		(1,569	)
Interest income		1,089			719			2,016			1,183
Other income (expenses)		175			(91	)		321			13
Income before income taxes		17,454			32,159			46,583			45,044
Income tax expense		(3,912	)		(11,299	)		(10,472	)		(8,339	)
Net Income		13,542			20,860			36,111			36,705
Less: Income attributable to non-controlling interests		(5,845	)		(5,906	)		(14,329	)		(10,898	)
Net income attributable to shareholders of Sinovac		7,697			14,954			21,782			25,807
Net income		13,542			20,860			36,111			36,705
Other comprehensive income (loss), net of tax of nil
Foreign currency translation adjustments		(5,569	)		4,581			(10,996	)		8,098
Comprehensive income		7,973			25,441			25,115			44,803
Less: comprehensive income attributable to non-controlling interests		(4,741	)		(6,752	)		(12,507	)		(12,089	)
Comprehensive income attributable to shareholders of Sinovac	$	3,232		$	18,689			12,608		$	32,714
Earnings per share
Basic net income per share		0.11			0.26			0.34			0.45
Diluted net income per share		0.11			0.26			0.34			0.45
Weighted average number of shares of common stock outstanding
Basic		70,993,470			57,052,268			64,727,146			57,033,816
Diluted		71,257,734			57,250,279			64,977,554			57,101,191

SINOVAC BIOTECH LTD.

Consolidated Statements of Cash Flows

For the six and twelve months ended December 31, 2018 and 2017

(Expressed in thousands of U.S. Dollars)                

	Six months ended						Tweleve months ended
	December 31						December 31
	2018			2017			2018			2017
	(Unaudited)			(Unaudited)
Cash flows provided by operating activities
Net income		13,542			20,860			36,111			36,705
Adjustments to reconcile net income to net cash provided by operating activities:
- Deferred income taxes		4,609			(2,743	)		3,146			(4,921	)
- Share-based compensation		1,474			495			4,305			979
- Inventory provision		53			957			2,529			1,231
- Provision (recovery) for doubtful accounts		(1,756	)		407			820			934
- Loss on disposal and impairment of property, plant and equipment		57			29			75			42
- Depreciation of property, plant and equipment and amortization of licenses		2,398			2,515			4,887			4,638
- Amortization of prepaid land lease payments		120			126			249			243
- Government grants recognized in income		(150	)		(137	)		(197	)		(141	)
Changes in:
- Accounts receivable		26,196			17,223			(13,082	)		(13,482	)
- Inventories		(3,992	)		(1,933	)		(9,412	)		(5,531	)
- Income tax payable		(6,410	)		9,237			(11,844	)		4,948
- Prepaid expenses and deposits		(2,188	)		(1,062	)		(2,613	)		(622	)
- Deferred revenue		3,014			3,460			(892	)		987
- Accounts payable and accrued liabilities		(16,149	)		7,934			(6,167	)		33,416
- Other non-current liablitites		28			330			28			330
Net cash provided by operating activities		20,846			57,698			7,943			59,756
Cash flows provided by (used in) financing activities
- Proceeds from bank loans		5,498			17,465			18,898			28,636
- Repayments of bank loans		(20,095	)		(20,760	)		(43,886	)		(38,708	)
- Proceeds from issuance of common stock, net of share issuance costs		83,673			1,229			85,304			1,264
- Proceeds from shares subscribed		64			428			64			428
- Government grants received		2,995			2,506			3,800			2,598
- Loan from a non-controlling shareholder		-			4,440			-			4,440
Net cash provided by (used in) financing activities		72,135			5,308			64,180			(1,342	)
Cash flows used in investing activities
- Purchase of short-term investments		(19,670	)		-			(19,670	)		-
- Proceeds from disposal of equipment		22			19			22			19
- Acquisition of property, plant and equipment		(2,754	)		(5,147	)		(5,613	)		(11,915	)
Net cash used in investing activities		(22,402	)		(5,128	)		(25,261	)		(11,896	)
Effect of exchange rate changes on cash and cash equivalents and restricted cash		(519	)		3,107			(4,656	)		4,005
Increase in cash and cash equivalents and restricted cash		70,060			60,985			42,206			50,523
Cash and cash equivalents and restricted cash, beginning of period		88,110			54,979			115,964			65,441
Cash and cash equivalents and restricted cash, end of period		158,170			115,964			158,170		$	115,964

SINOVAC BIOTECH LTD.

Reconciliations of Non-GAAP measures to the nearest comparable GAAP measures

For the six and twelve months ended December 31, 2018 and 2017

(Expressed in thousands of U.S. Dollars, except for numbers of shares and per share data)             

	Six months ended December 31						Twelve months ended December 31
	2018			2017			2018			2017
	(Unaudited)			(Unaudited)			(Unaudited)			(Unaudited)
Net income		13,542			20,860			36,111			36,705
Adjustments:
Share-based compensation		1,474			495			4,305			979
Depreciation and amortization		2,518			2,641			5,136			4,881
Interest and financing expenses, net of interest income		(669	)		28			(946	)		386
Net other (income) expense		(175	)		91			(321	)		(13	)
Income tax expense		3,912			11,299			10,472			8,339
Non-GAAP adjusted EBITDA		20,602			35,414			54,757			51,277
Net income		13,542			20,860			36,111			36,705
Add: Foreign exchange (gain) loss		853			(1,188	)		(559	)		(1,323	)
Add: Share-based compensation		1,474			495			4,305			979
Non-GAAP net income		15,869			20,167			39,857			36,361
Net Income attributable to shareholders of Sinovac		7,697			14,954			21,782			25,807
Add: Non-GAAP adjustments to net income		1,345			(693	)		2,764			(344	)
Non-GAAP net income attributable to shareholders of Sinovac for computing non-GAAP diluted earnings (loss) per share		9,042			14,261			24,546			25,463
Weighted average number of shares on a diluted basis		71,257,734			57,250,279			64,977,554			57,101,191
Diluted earnings per share		0.11			0.26			0.34			0.45
Add: Non-GAAP adjustments to net income per share		0.02			(0.01	)		0.04			(0.01	)
Non-GAAP Diluted earnings per share		0.13			0.25			0.38			0.44