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): March 12, 2015

MARCUS & MILLICHAP, INC.

(Exact name of Registrant as Specified in its Charter)

23975 Park Sorrento, Suite 400

Calabasas, California 91302

(Address of Principal Executive Offices including Zip Code)

(818) 212-2250

(Registrant’s Telephone Number, including Area Code)

Not Applicable

(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 March 12, 2015, Marcus & Millichap, Inc. (the “Company”) entered into an Underwriting Agreement (the “Underwriting Agreement”) with Phoenix Investments Holdings LLC, The Marcus Family Foundation (together, the “Selling Stockholders”), Citigroup Global Markets Inc., Barclays Capital Inc. and Wells Fargo Securities, LLC, as representatives of the several underwriters, relating to an underwritten public offering of up to 4,600,000 shares (the “Shares”) of its common stock by the Selling Stockholders, including up to 600,000 shares that may be sold pursuant to an option granted to the underwriters. The Shares will be sold pursuant to an effective shelf registration statement on Form S-3, File No. 333-201924, which became effective on February 25, 2015. The foregoing description of the Underwriting Agreement is qualified in its entirety by reference to the copy thereof, which is filed herewith as Exhibit 1.1 and is incorporated herein by reference.

On March 12, 2015, the Company issued a press release announcing the pricing of the Shares. A copy of the press release is furnished as Exhibit 99.1 to this Current Report and is incorporated herein by reference.

The information furnished on this Form 8-K relating to the Company’s press release regarding the pricing of the Shares, including Exhibit 99.1 attached, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any other filing under the Securities Act of 1933, as amended or the Exchange Act, except as expressly set forth by specific reference in such a filing.

(d) Exhibits.

2

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.

3

EXHIBIT INDEX