UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form SD

Specialized Disclosure Report

Thoratec Corporation

(Exact name of the registrant as specified in its charter)

Taylor C. Harris, (925) 847-8600

(Name and telephone number, including area code, of person to contact in connection with this
report)

Check the appropriate box to indicate the rule pursuant to which this form is being filed, and provide the period to which the information in this form applies:

x                                  Rule 13p-1 under the Securities Exchange Act (17 CFR 240.13p-1) for the reporting period from January 1 to December 31, 2014.

Section 1—Conflict Minerals Disclosure

Item 1.01 Conflict Minerals Disclosure and Report

Conflict Minerals Disclosure

This Form SD of Thoratec Corporation (the “Company”) is filed pursuant to Rule 13p-1 promulgated under the Securities Exchange Act of 1934 for the reporting period January 1, 2014 to December 31, 2014.

A copy of the Company’s Conflict Minerals Report is provided as Exhibit 1.01 to this Form SD, and is publicly available on the Company’s website at http://phx.corporate-ir.net/phoenix.zhtml?c=95989&p=irol-govHighlights.

Item 1.02 Exhibit

As specified in Section 2, Item 2.01 of this Form SD, the Company is hereby filing its Conflict Minerals Report as Exhibit 1.01 to this report.

Section 2—Exhibits

Item 2.01 Exhibits

The following exhibit is filed as part of this report.

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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 duly authorized undersigned.

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EXHIBIT INDEX

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