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 3, 2014

FS Investment Corporation

(Exact name of Registrant as specified in its charter)

Registrant’s telephone number, including area code: (215) 495-1150

None

(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 December 3, 2014, FS Investment Corporation (the “Company”) and U.S. Bank National Association (the “Trustee”), entered into a Second Supplemental Indenture (the “Second Supplemental Indenture”) to the Indenture, dated July 14, 2014, between the Company and the Trustee (the “Base Indenture”, and together with the Second Supplemental Indenture, the “Indenture”). The Second Supplemental Indenture relates to the Company’s issuance of $325,000,000 aggregate principal amount of its 4.250% notes due 2020 (the “Notes”).

The Notes will mature on January 15, 2020 and may be redeemed in whole or in part at the Company’s option at any time or from time to time at the redemption prices set forth in the Indenture. The Notes bear interest at a rate of 4.250% per year payable semi-annually on January 15^th and July 15^th of each year, commencing on July 15, 2015. The Notes are general unsecured obligations of the Company that rank senior in right of payment to all of the Company’s existing and future indebtedness that is expressly subordinated in right of payment to the Notes, rank pari passu with all existing and future unsecured unsubordinated indebtedness issued by the Company, rank effectively junior to any of the Company’s secured indebtedness (including unsecured indebtedness that the Company later secures) to the extent of the value of the assets securing such indebtedness, and rank structurally junior to all existing and future indebtedness (including trade payables) incurred by the Company’s subsidiaries, financing vehicles or similar facilities.

The Indenture contains certain covenants, including covenants requiring the Company to comply with the asset coverage requirements of Section 18(a)(1)(A) as modified by Section 61(a)(1) of the Investment Company Act of 1940, as amended, whether or not it is subject to those requirements, and to provide financial information to the holders of the Notes and the Trustee if the Company is no longer subject to the reporting requirements under the Securities Exchange Act of 1934, as amended. These covenants are subject to important limitations and exceptions that are described in the Indenture.

In addition, on the occurrence of a “change of control repurchase event,” as defined in the Indenture, the Company will generally be required to make an offer to purchase the outstanding Notes at a price equal to 100% of the principal amount of such Notes plus accrued and unpaid interest to the repurchase date.

The Notes were offered and sold in an offering registered under the Securities Act of 1933, as amended, pursuant to the Registration Statement on Form N-2 (File No. 333-195863), the prospectus supplement dated November 25, 2014 and the pricing term sheet filed with the U.S. Securities and Exchange Commission on November 25, 2014. The transaction closed on December 3, 2014. The net proceeds to the Company were approximately $320.5 million, after deducting the underwriting discounts and commissions of approximately $2.9 million payable by the Company and estimated offering expenses of approximately $350,000 payable by the Company. The Company has used the net proceeds to repay outstanding indebtedness under its financing facilities.

The foregoing descriptions of the Second Supplemental Indenture and the Notes do not purport to be complete and are qualified in their entirety by reference to the full text of the Second Supplemental Indenture and the Notes, respectively, each filed as exhibits hereto and incorporated by reference herein.

The information required by Item 2.03 contained in Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference.

(d) Exhibits.

SIGNATURE

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.

EXHIBIT INDEX