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): December 16, 2011

Discover Card Execution Note Trust

(Exact name of issuing entity in respect of the notes as specified in charter)

Discover Card Master Trust I

(Exact name of issuing entity in respect of the Series 2007-CC Collateral Certificate as specified in charter)

Discover Bank

(Exact name of sponsor and depositor as specified in charter)

Registrant’s Telephone Number, including area code: (302) 323-7315

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:

Increase in Principal Amount of Class D(2009-1) Notes. On December 16, 2011, Discover Bank, pursuant to Section 2.03 of the Note Purchase Agreement (the “Note Purchase Agreement”), dated as of July 2, 2009, among Discover Card Execution Note Trust, as Issuer, Discover Bank, as Depositor, and the purchasers named therein and Section 2.06 of the Class D(2009-1) Terms Document, dated as of July 2, 2009, as the same may be further amended, supplemented, restated, amended and restated, replaced or otherwise modified from time to time, by and between Discover Card Execution Note Trust, as Issuer, and U.S. Bank National Association as Indenture Trustee, increased the Outstanding Dollar Principal Amount of the Class D(2009-1) Notes. The Outstanding Dollar Principal Amount of the Class D(2009-1) Notes was increased to satisfy the increase in the required subordinated amounts of DiscoverSeries Notes that will occur following the final payment date for the Series 2009-SD Certificates, which is expected to be January 17, 2012. The increase in the Outstanding Dollar Principal Amount of the Class D(2009-1) Notes was in the amount of $241,683,596, resulting in an Outstanding Dollar Principal Amount of the Class D(2009-1) Notes of $1,730,454,546. The Class D(2009-1) Notes were sold to purchasers in reliance upon the exemption contained in Section 4(2) of the Securities Act of 1933, as amended. The Notes were sold at par value for cash, with no applicable underwriting discounts or commissions. In connection with this increase, the investor interest in receivables represented by the collateral certificate issued by the Discover Card Master Trust I that secures the DiscoverSeries Notes was increased by $241,683,596. Discover Card Execution Note Trust paid the net proceeds from the issuance to Discover Bank in exchange for the increase in the investor interest in receivables represented by the collateral certificate.

Increase in Series Investor Interest of Series 2009-SD Certificates. On December 16, 2011, Discover Bank, pursuant to Section 2.03 of the Certificate Purchase Agreement (the “Certificate Purchase Agreement”), dated as of September 23, 2009, among Discover Bank, as Master Servicer, Servicer, and Seller, and the purchasers named therein and Section 31 of the Series Supplement, dated as of September 23, 2009, as the same may be amended, supplemented, restated, amended and restated, replaced or otherwise modified from time to time, by and between Discover Bank, as Master Servicer, Servicer, and Seller, and U.S. Bank National Association, as Trustee, increased the Series Investor Interest of the Series 2009-SD Certificates. The total increase in the Series Investor Interest of the Series 2009-SD Certificates was in the amount of $4,833,672, which resulted in a Series Investor Interest of the Series 2009-SD Certificates of $346,419,532. The Series 2009-SD Certificates were sold to purchasers in reliance upon the exemption contained in Section 4(2) of the Securities Act of 1933, as amended. The Certificates were sold at par value for cash, with no applicable underwriting discounts or commissions. The Series 2009-SD Certificates are expected to mature on January 17, 2012.

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.