UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 14, 2015

Santander Holdings USA, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (617) 346-7200

n/a

(Former name or former address if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On April 17, 2015, Santander Holdings USA, Inc. (the “Company”) completed the public offer and sale of $1,000,000,000 aggregate principal amount of its 2.650% Senior Notes due 2020 (the “Notes”). The Notes were issued pursuant to a Senior Debt Indenture dated April 19, 2011 (the “Senior Debt Indenture”) between the Company and Deutsche Bank Trust Company Americas, as trustee (the “Trustee”), as supplemented by a Fourth Supplemental Indenture dated April 17, 2015 (the “Fourth Supplemental Indenture”) between the Company and the Trustee. The Notes were sold pursuant to an underwriting agreement dated April 14, 2015 (the “Underwriting Agreement”) between the Company and Barclays Capital Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated and Santander Investment Securities Inc. The Underwriting Agreement, Senior Debt Indenture, Fourth Supplemental Indenture and form of Notes are attached to this Current Report on Form 8-K as Exhibits 1.1, 4.1, 4.2, and 4.3, respectively, and are incorporated into this Item 8.01 by reference.

The Underwriting Agreement, the Senior Debt Indenture, the Fourth Supplemental Indenture and the Notes are more fully described in the prospectus supplement filed with the Securities and Exchange Commission (the “Commission”) on April 16, 2015, to the accompanying prospectus filed with the Commission on March 15, 2013 as part of the Company’s Registration Statement on Form S-3 (File No. 333-187307) (the “Registration Statement”). The foregoing descriptions of the Underwriting Agreement, the Senior Debt Indenture, the Fourth Supplemental Indenture and the Notes do not purport to be complete and are qualified in their entirety by reference to Exhibits 1.1, 4.1, 4.2 and 4.3, respectively.

This Current Report on Form 8-K is being filed, in part, for the purpose of filing the attached documents as exhibits to the Registration Statement in connection with the issuance of the Notes, and such exhibits are hereby incorporated by reference into the Registration Statement.

(d) Exhibits

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 hereunto duly authorized.

EXHIBIT INDEX