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)

May 3, 2016

ILLINOIS POWER GENERATING COMPANY

(Exact name of registrant as specified in its charter)

(713) 507-6400

(Registrant’s telephone number, including area code)

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:

o                                    Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o                                    Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o                                    Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o                                    Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 7.01              Regulation FD Disclosure

On May 3, 2016, Dynegy Inc. (“Dynegy”), the indirect parent of Illinois Power Generating Company (the “Company”) announced its first quarter financial results and affirmed its 2016 guidance estimates. Dynegy’s earnings presentation slides makes reference to potential restructuring options and certain financial information regarding the Company. Dynegy’s earnings presentation and management comments on the earnings presentation will be available on the “Investor Relations” section of Dynegy’s website (www.dynegy.com) later today.

The presentation slides and comments include statements intended as “forward-looking statements,” which are subject to the cautionary statement about forward-looking statements set forth therein. Certain of the slides also contain non-GAAP financial information. Reconciliations of these measures to the most directly comparable GAAP financial measures, to the extent available without unreasonable effort, are contained in the presentation slides. To the extent required, statements disclosing the definitions, utility and purposes of these measures are set forth in Dynegy’s Current Report on Form 8-K filed with the SEC on May 3, 2016.

2

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.

3