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 17, 2015

FIRST NATIONAL MASTER NOTE TRUST

FIRST NATIONAL FUNDING LLC

FIRST NATIONAL BANK OF OMAHA

(Exact name of Issuing Entity, Depositor/Registrant and Sponsor, as specified in their respective charters)

Nebraska

(State of Incorporation)

(402) 341-0500

(Registrant’s telephone number, including area code)

Not applicable

(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:

Entry into Indenture Supplement

On September 17, 2015, First National Master Note Trust and U.S. Bank National Association, as indenture trustee (the “Indenture Trustee”), entered into the Series 2015-1 Indenture Supplement (the “Series 2015-1 Indenture Supplement”), a copy of which is filed with this Form 8-K as Exhibit 4.1.

Issuance of Series 2015-1 Asset Backed Notes

Reference is made to the registration statement (the “Registration Statement”) on Form S-3 (File No. 333-190006) filed with the Securities and Exchange Commission on July 24, 2013 (as amended by pre-effective Amendment No. 1 filed on September 17, 2013 and pre-effective Amendment No. 2 filed on September 25, 2013) and declared effective on September 30, 2013. On September 17, 2015 First National Master Note Trust publicly issued $300,000,000 of Class A Series 2015-1 Asset Backed Notes (the “Class A Notes”) described in a Prospectus Supplement dated September 10, 2015 to a Prospectus dated September 10, 2015.

On September 17, 2015 First National Master Note Trust also issued $40,385,000 of Class B Series 2015-1 Asset Backed Notes (the “Class B Notes”) and $44,231,000 of Class C 2015-1 Asset Backed Notes (the “Class C Notes”) to First National Bank of Omaha, a national banking association (“FNBO”) and an affiliate of First National Master Note Trust. The Class B Notes and Class C Notes were offered and sold without registration under the Securities Act of 1933, as amended (the “Act”), in reliance on the exemption set forth in Section 4(2) of the Act.

Use of Proceeds – Class A Notes

The public offering of the Class A Notes was made under the Registration Statement and was terminated on September 17, 2015 upon the sale of all of the Class A Notes. The underwriters of the Class A Notes were RBC Capital Markets, LLC, J.P. Morgan Securities LLC and Wells Fargo Securities, LLC.

During the period from the effective date of the Registration Statement, through the current reporting period, the amount of expenses incurred in connection with the issuance and distribution of the publicly offered and sold Class A Notes with respect to underwriting commissions and discounts was $1,050,000. After deducting the underwriting discounts described in the preceding sentence, the net offering proceeds to the Issuer before expenses for the Class A Notes are $298,950,000. Other expenses, including legal fees and other costs and expenses relating the offer of the Class A Notes, are reasonably estimated to be $499,595 and net proceeds from the sale of the Class A Notes to the Issuer, after deduction of expenses, are reasonably estimated to be $298,450,405. With respect to the payment of these other expenses and costs, all direct or indirect payments were made to persons other than persons who are (a) directors or officers of the Issuer, or (b) owners of 10 percent or more of any class of securities of the Issuer.

The net proceeds from the sale of the Class A Notes, after deducting the underwriting commissions and discounts, and expenses above, were used to purchase credit card receivables from FNBO. Except as provided in the previous sentence, none of the proceeds were used for payments to (a) any directors or officers of the Issuer or (b) owners of 10 percent or more of any class of securities of the Issuer.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.