UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K/A

(Amendment No. 1)

For the fiscal year ended December 31, 2017

or

For the transition period from                 to                

Commission file number: 000-30171

SANGAMO THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

(510) 970-6000

(Registrant’s telephone number, including area code)

None

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ☒    No  ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.    Yes  ☐    No  ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ☒    No  ☐

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ☒    No  ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ☒

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or emerging growth company. See definition of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ☐    No  ☒

The aggregate market value of the voting stock held by non-affiliates of the registrant based upon the closing sale price of the common stock on June 30, 2017 (the last business day of the registrant’s most recently completed second fiscal quarter), as reported on the Nasdaq Global Select Market was $734,155,954. For purposes of this calculation, directors and executive officers of the registrant have been deemed affiliates. This determination of affiliate status is not necessarily a conclusive determination for other purposes.

As of February 15, 2018, a total of 86,338,976 shares of common stock $0.01 par value per share were outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Certain information required by Part III, Items 10-14 of this Form 10-K is incorporated by reference to the registrant’s definitive Proxy Statement for the 2018 Annual Meeting of Stockholders to be filed with the Securities and Exchange Commission pursuant to Regulation 14A not later than 120 days after the end of the fiscal year covered by this Form 10-K, provided that if such Proxy Statement is not filed within such period, such information will be included in an amendment to this Form 10-K to be filed within such 120-day period.

TABLE OF CONTENTS

Form 10-K/A

(Amendment No. 1)

PART IV

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EXPLANATORY NOTE

Sangamo Therapeutics, Inc. (the “Company”) is filing this Amendment No. 1 to Annual Report on Form 10-K/A (this “Amendment”) to amend the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017, as filed with the Securities and Exchange Commission (the “SEC”) on March 1, 2018 (the “Form 10-K”). This Amendment is being filed solely to re-file Exhibit 10.40 to the Form 10-K (the “Exhibit”) and in connection therewith, to amend Part IV, Item 15 of the Form 10-K. Certain provisions of the Exhibit were redacted in accordance with the Company’s application for confidential treatment with the SEC. In response to SEC comments, the Exhibit, as re-filed, restores certain provisions that had previously been redacted. In addition, as required by Rule 12b-15 under the Securities Exchange Act of 1934, as amended, new certifications by the Company’s principal executive officer and principal financial officer are filed as exhibits to this Amendment.

No attempt has been made in this Amendment to modify or update the other disclosures presented in the Form 10-K. This Amendment does not reflect events occurring after the filing of the original Form 10-K (i.e., those events occurring after March 1, 2018) or modify or update those disclosures that may be affected by subsequent events. Such subsequent matters are addressed in subsequent reports filed with the SEC. Accordingly, this Amendment should be read in conjunction with the Form 10-K and the Company’s other filings with the SEC.

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PART IV

ITEM 15 – EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

(a) The following documents are included as part of the Company’s Annual Report on Form 10-K filed with the SEC on March 1, 2018 (the “Form 10-K”):

1. Financial Statements—See Index to Consolidated Financial Statements in Item 8 of the Form 10-K.

2. Financial Statement Schedules—Not Applicable.

3. Exhibits

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this Amendment No. 1 to its Annual Report on Form 10-K/A to be signed on its behalf by the undersigned, thereunto duly authorized.