UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 13D

(Rule 13d-101)

Information to be Included in Statements Filed Pursuant

to § 240.13d-1(a) and Amendments Thereto Filed

Pursuant to § 240.13D-2(a)

Under the Securities Exchange Act of 1934

(Amendment No. 1)

Rapid7, Inc.

(Name of Issuer)

Common Stock, $0.01

par value per share

(Title of Class of Securities)

753422 10 4

(CUSIP Number)

Bain Capital Venture Investors, LLC

200 Clarendon Street

Boston, MA 02116

617-516-2000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

June 6, 2017

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ☐

Note. Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.

13D

13D

13D

13D

This Amendment No. 1 to Schedule 13D relates to common stock, $0.01 par value per share (the “Common Stock”), of Rapid7, Inc., a Delaware corporation (the “Issuer”), and amends the initial statement on Schedule 13D filed by the Reporting Persons relating to the Common Stock on August 3, 2015 (the “Initial Statement” and, as amended by this Amendment No. 1, the “Schedule 13D”). Capitalized terms used but not defined herein have the meanings given to them in the Initial Statement.

Item 2 of the Initial Statement is hereby amended and restated as follows:

(a) This Schedule 13D is being filed jointly by each of the following (each, a “Reporting Person” and collectively, the “Reporting Persons”): Bain Capital Venture Fund 2007, L.P., a Delaware limited partnership (“BCVF”), BCIP Venture Associates, a Delaware partnership (“BCIPVA”), and BCIP Venture Associates-B, a Delaware partnership (“BCIPVB”).

Bain Capital Venture Partners 2007, L.P., a Delaware limited partnership (“BCVP”), is the general partner of BCVF. Bain Capital Venture Investors, LLC, a Delaware limited liability company (“BCVI”), is the general partner of BCVP.

Boylston Coinvestors, LLC (“Boylston”), a Delaware limited liability company, is the managing partner of BCIPVA and BCIPVB.

The governance, investment strategy and decision-making process with respect to the investments held by all of the Reporting Persons is directed by the Executive Committee of BCVI. The Executive Committee of BCVI consists of Michael A. Krupka and Ajay Agarwal. As a result, BCVI and Messrs. Krupka and Agarwal may be deemed to share voting and dispositive power with respect to the securities held by all of the Reporting Persons.

The Reporting Persons have entered into a Joint Filing Agreement, dated August 3, 2015, a copy of which was filed with the Initial Statement as an exhibit, pursuant to which the Reporting Persons have agreed to file this statement jointly in accordance with the provisions of Rule 13d-1(k)(1) promulgated by the Securities and Exchange Commission under Section 13 of the Act.

(b) The principal business address of each of the Reporting Persons, Boylston, BCVP, BCVI and Messrs. Krupka and Agarwal is c/o Bain Capital Venture Investors, LLC, 200 Clarendon Street, Boston, Massachusetts 02116.

(c) The Reporting Persons, Boylston, BCVP and BCVI are principally engaged in the business of investment in securities. Messrs. Krupka and Agarwal are Managing Directors of BCVI.

(d) During the last five years, none of the Reporting Persons, Boylston, BCVP, BCVI or Messrs. Krupka or Nye have been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e) During the last five years, none of the Reporting Persons, Boylston, BCVP, BCVI or Messrs. Krupka or Nye have been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violation of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f) Each of the Reporting Persons, Boylston, BCVP and BCVI are organized under the laws of the State of Delaware. Messrs. Krupka and Agarwal are citizens of the United States.

13D

Item 5 of the Initial Statement is hereby amended and restated as follows:

(a) – (c) The information contained on the cover pages and Item 2 of this Schedule 13D is hereby incorporated herein by reference. The following disclosure assumes that there are 43,409,436 shares of Common Stock issued and outstanding as of June 5, 2017, which the Issuer represented in the prospectus filed with the Securities and Exchange Commission pursuant to Rule 424(b) on the date hereof (the “Prospectus”).

On June 6, 2017, BCVF sold 1,223,772 shares of Common Stock, BCIPVA sold 174,053 shares of Common Stock and BCIPVB sold 2,175 shares of Common Stock. The shares were sold pursuant to the Prospectus at a price of $18 per share.

After giving effect to the transactions described above, BCVF holds 6,626,923 shares of Common Stock, representing 15.3% of the shares of Common Stock outstanding, BCIPVA holds 942,527 shares of Common Stock, representing 2.2% of the shares of Common Stock outstanding, and BCIPVB holds 11,780 shares of Common Stock, representing less than 0.1% of the shares of Common Stock outstanding.

(d) Except as otherwise described in this Item 5, no one other than the Reporting Persons has the right to receive, or the power to direct the receipt of, dividends from, or the proceeds from the sale of, any of the Common Stock beneficially owned by the Reporting Persons as described in this Item 5.

(e) Not applicable.

13D

SIGNATURES

After reasonable inquiry and to the best of its knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: June 7, 2017