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): November 30, 2018

Vivint Solar, Inc.

(Exact name of registrant as specified in its charter)

1800 West Ashton Blvd

Lehi, Utah 84043

(Address of principal executive offices, including zip code)

(877) 404-4129

(Registrant’s telephone number, including area code)

(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 (see General Instruction A.2. below):

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.  ☒

On November 29, 2018, Vivint Solar, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) by and among the Company, 313 Acquisition LLC (the “Selling Stockholder”) and Merrill Lynch, Pierce, Fenner & Smith Incorporated, as representative of the several underwriters named therein (collectively the “Underwriters”), relating to an underwritten public offering of 8,000,000 shares of common stock of the Company (the “Underwritten Shares”) by the Selling Stockholder. The Company will not receive any of the proceeds from the sale of the shares of the Company’s common stock in this offering. The Selling Stockholder has granted the Underwriters a 30-day option to purchase up to an additional 1,200,000 shares of common stock (together with the Underwritten Shares, the “Shares”).

The offering is being made pursuant to the Company’s effective registration statement on Form S-3 (Registration Statement No. 333-227014) previously filed with the Securities and Exchange Commission and a related prospectus included in the Registration Statement, as supplemented by a preliminary prospectus supplement dated November 29, 2018 and a final prospectus supplement dated November 29, 2018.

The Underwriting Agreement contains customary representations, warranties and agreements by the Company and the Selling Stockholder, customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act, other obligations of the parties and termination provisions.

The Underwriting Agreement is filed as Exhibit 1.1 to this report, which is incorporated by reference herein, and the description of the terms of the Underwriting Agreement is qualified in its entirety by reference to such exhibit. A copy of the opinion of Wilson Sonsini Goodrich & Rosati, Professional Corporation, relating to the legality of the sale of the Shares in the offering is attached as Exhibit 5.1 hereto and is incorporated by reference herein.

Item 9.01 Financial Statements and Exhibits

(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 hereunto duly authorized.

Date: November 30, 2018