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): September 30, 2015

51-0020270

(IRS Employer Identification No. of the sponsor and depositor)

(302) 323-7315

(Telephone, including area code)

Former name or former address, if changed since last report: Not Applicable

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 September 30, 2015, Discover Card Execution Note Trust and Discover Bank entered into an Underwriting Agreement by and among Discover Card Execution Note Trust, Discover Bank, Deutsche Bank Securities Inc. and RBC Capital Markets, LLC (the “Underwriting Agreement”), with respect to notes to be issued by Discover Card Execution Note Trust in one or more series, classes and tranches pursuant to the Indenture, dated as of July 26, 2007, as amended by the First Amendment to Indenture, dated as of June 4, 2010, and as supplemented by the Amended and Restated Indenture Supplement, dated as of June 4, 2010, and a Terms Document having the date stated in the applicable Terms Agreement (as so supplemented and as otherwise modified or amended from time to time, the “Indenture”), between Discover Card Execution Note Trust, as Issuer, and U.S. Bank National Association, as Indenture Trustee. A copy of the Underwriting Agreement is filed as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated herein by reference.

On September 30, 2015, Discover Card Execution Note Trust and Discover Bank entered into a Terms Agreement with Deutsche Bank Securities Inc. and RBC Capital Markets, LLC, with respect to the issuance of $675,000,000 principal amount of Class A(2015-3) DiscoverSeries Notes of Discover Card Execution Note Trust (the “Class A(2015-3) Terms Agreement”). A copy of the Class A(2015-3) Terms Agreement is filed as Exhibit 1.2 to this Current Report on Form 8-K and is incorporated herein by reference.

On October 7, 2015, Discover Card Execution Note Trust, as Issuer, and U.S. Bank National Association, as Indenture Trustee, intend to enter into the Class A(2015-3) Terms Document. An unexecuted copy of the Class A(2015-3) Terms Document is filed as Exhibit 4.1 to this Current Report on Form 8-K and is incorporated herein by reference.

SIGNATURES

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.

INDEX TO EXHIBITS