UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 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 14, 2017

VISTRA ENERGY CORP.

(Exact name of registrant as specified in its charter)

(214) 812-4600

(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:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Effective December 14, 2017 (the “Effective Date”), Vistra Operations Company LLC (“Vistra Operations”), an indirect wholly owned subsidiary of Vistra Energy Corp. (the “Company”), entered into an amendment (the “Repricing Amendment”) to that certain Credit Agreement, dated as of October 3, 2016 (as amended from time to time, the “Credit Facilities”), among Vistra Operations, as Borrower, and Deutsche Bank AG New York Branch, as Administrative and Collateral Agent, and the other parties named therein. As a result of the Repricing Amendment, the interest rate on the outstanding $2.829 billion Initial Term Loans, (ii) outstanding $650 million Initial Term C Loans (reduced by $150 million to $500 million outstanding as described herein) and (iii) Revolving Credit Loans (each as defined in the Credit Facilities) were reduced and, effective as of the Effective Date, bears interest at a rate equal to, at Vistra Operations’ option, either LIBOR (subject to a LIBOR floor of 0.75%) plus an applicable margin of 2.50% or a base rate plus an applicable margin of 1.50%. The Initial Term Loans and Initial Term C Loans are prepayable at any time without premium or penalty; provided that there will be a 1.00% pre-payment premium in connection with any repricing of such term loans that reduces the interest rate prior to June 14, 2018. The Repricing Amendment did not change the interest rate on the outstanding $993 million 2016 Incremental Term Loans (as defined in the Credit Facilities) incurred under the Credit Facilities on December 14, 2016. The 2016 Incremental Term Loans will continue to bear interest at a rate equal to, at Vistra Operations’ option, either LIBOR (subject to a LIBOR floor of 0.75%) plus an applicable margin of 2.75% or a base rate plus an applicable margin of 1.75%.

In connection with the Repricing Amendment, Vistra Operations also made a partial paydown to its Initial Term C Loan lenders in the amount of $150 million, and increased the Revolving Letter of Credit Commitment from $600 million to $715 million. The total Revolving Credit Commitment remained unchanged at $860 million. As a result of the Repricing Amendment and subsequent partial paydown of Initial Term C Loans, Vistra Operations expects that its annual interest expense with respect to the Credit Facilities will decrease by approximately $12 million (on a pre-tax basis and excluding one-time fees and expenses of approximately $3 million incurred in connection with the Repricing Amendment).

A copy of the Repricing Amendment is included as Exhibit No. 10.1 to this Current Report and is incorporated herein by reference. The above description of the Repricing Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Repricing Amendment.

(d) Exhibits

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.