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): April 25, 2017

MARRONE BIO INNOVATIONS, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (530) 750-2800

(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 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.   ☒

Item 1.01 Entry Into a Material Definitive Agreement.

Common Stock Offering

On April 25, 2017, Marrone Bio Innovations, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with National Securities Corporation, (the “Underwriter”), in connection with a registered firm commitment underwritten public offering (the “Offering”) of 5,714,286 shares of the Company’s common stock, par value $0.00001 per share (“Common Stock”). Subject to the terms and conditions of the Underwriting Agreement, the Company has agreed to sell to the Underwriter, and the Underwriter has agreed to purchase from the Company, an aggregate of 5,714,286 shares of Common Stock. Pursuant to the Underwriting Agreement, the Company also granted the Underwriter a 45-day option to purchase up to an additional 857,143 shares of its Common Stock to cover over-allotments, if any.

The Underwriting Agreement contains customary representations, warranties and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriter, including for liabilities under the Securities Act of 1933, as amended, other obligations of the parties and termination provisions. The representations, warranties and covenants contained in the Underwriting Agreement were made only for purposes of such agreement and as of specific dates, were solely for the benefit of the parties to such agreement, and may be subject to limitations agreed upon by the contracting parties.

Pursuant to the terms of the Underwriting Agreement and related lock-up agreements, the Company and all of its directors and executive officers also agreed not to sell or transfer any Common Stock held by them for 90 days after April 25, 2017 without first obtaining the written consent of the Underwriter, subject to certain exceptions, extensions and terms as set forth in the Underwriting Agreement.

The shares of Common Stock will be issued pursuant to a shelf registration statement on Form S-3 (Registration Statement No. 333-215024) (the “Registration Statement”) previously filed with the Securities and Exchange Commission (the “SEC”) on December 9, 2016, amended on December 29, 2016 and declared effective by the SEC on January 6, 2017, including the preliminary prospectus supplement dated April 24, 2017 and a prospectus supplement dated April 25, 2017, to the prospectus contained in the Registration Statement dated December 29, 2016.

A copy of the Underwriting Agreement is filed as Exhibit 1.1 to this Current Report and is incorporated herein by reference, and the description of the terms of the Underwriting Agreement is qualified in its entirety by reference to such exhibit. The Underwriting Agreement is also filed with reference to, and is hereby incorporated by reference into, the Registration Statement.

Attached as Exhibit 5.1 to this Current Report and incorporated herein by reference is a copy of the opinion of Morrison & Foerster LLP relating to the validity of the shares of Common Stock that may be sold in the Offering (the “Legal Opinion”). The Legal Opinion is also filed with reference to, and is hereby incorporated by reference into, the Registration Statement.

Item 8.01 Other Events.

On April 25, 2017, the Company issued a press release announcing the pricing of the Common Stock in the Offering. A copy of the press release is filed as Exhibit 99.1 to this report and is incorporated herein by reference.

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.

EXHIBIT INDEX