UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED

PURSUANT TO § 240.13d-2(a)

(Amendment No. 3)

Under the Securities Exchange Act of 1934

MALIBU BOATS, INC.

(Name of Issuer)

Class A Common Stock, par value $0.01

(Title of Class of Securities)

56117J100

(CUSIP Number)

Jack D. Springer

Chief Executive Officer

5075 Kimberly Way

Loudon, Tennessee 37774

(865) 458-5478

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

May 27, 2015

(Date of Event Which Requires the 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 Rule 13d-1(e), 13d-1(f) or 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 Rule 13d-7(b) 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 or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

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Explanatory Note

This Amendment No. 3 to Schedule 13D is being filed to reflect the beneficial ownership of Class A Common Stock, par value $0.01 per share (the “Class A Common Stock”) of Malibu Boats, Inc. (the “Issuer”) following the closing of the public offering of Class A Common Stock by certain selling stockholders of the Issuer (the “Offering”) on May 27, 2015. This Amendment No. 3 to Schedule 13D does not reflect the ownership of Units in Malibu Boats Holdings, LLC (the “LLC Units”) held by the reporting persons. The reporting persons are not deemed to own shares of Class A Common Stock through the ownership of LLC Units because if the reporting persons were to request an exchange of the LLC Units to Class A Common Stock, the Issuer may, at the Issuer’s option, other than in the event of a change in control, elect to pay cash equal to the market value of the Class A Common Stock.

(a),(b),(c),(f) This statement is being filed by the following entities:

The entities and individuals listed in items (1) through (8) above are herein collectively referred to as the “Reporting Persons” and individually as a “Reporting Person.” For the purposes of this filing, the entities listed in items (1) through (6) above are herein collectively referred to as the “Black Canyon Affiliates.” The Canyon Value Realization Fund, L.P. and Loudon Partners, LLC are not listed as reporting persons in this Amendment No. 3 to Schedule 13D because they only owned LLC Units. The Canyon Value Realization Fund, L.P. and Loudon Partners, LLC were not deemed to own shares of Class A Common Stock through the ownership of LLC Units because if The Canyon Value Realization Fund, L.P. and Loudon Partners, LLC were to request an exchange of the LLC Units to Class A Common Stock, the Issuer may, at the Issuer’s option, other than in the event of a change in control, elect to pay cash equal to the market value of the Class A Common Stock.

Black Canyon Investments L.P. is the general partner of Black Canyon Direct Investment Fund L.P. and possesses the voting and dispositive power with respect to the securities

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beneficially owned by Black Canyon Direct Investment Fund L.P., including the securities held by BC-MB GP, a wholly-owned subsidiary of Black Canyon Direct Investment Fund L.P. Black Canyon Investments L.P. also possesses the voting power and dispositive power with respect to the securities beneficially owned by The Canyon Value Realization Fund, L.P. and The Canyon Value Realization Master Fund, L.P., pursuant to an agreement between Black Canyon Investments L.P. and The Canyon Value Realization Fund, L.P. and The Canyon Value Realization Master Fund, L.P. As a result, Black Canyon Investments L.P. may be deemed the beneficial owner of the securities beneficially owned by Black Canyon Direct Investment Fund L.P., The Canyon Value Realization Fund, L.P. and The Canyon Value Realization Master Fund, L.P. Black Canyon Investments LLC is the general partner of Black Canyon Investments L.P. and possesses the voting and dispositive power with respect to the securities beneficially owned by Black Canyon Investments L.P. and may be deemed the beneficial owner of the securities beneficially owned by Black Canyon Investments L.P. Black Canyon Capital LLC, as a managing member of Black Canyon Investments LLC, possesses the voting power with respect to the securities beneficially owned by Black Canyon Investments LLC and may be deemed the beneficial owner of the securities beneficially owned by Black Canyon Investments LLC. Mr. Hooks and Mr. Lanigan, both of whom are members of the board of directors of the Issuer, are managing directors of Black Canyon Capital LLC and therefore may each be deemed the beneficial owner of the securities beneficially owned by Black Canyon Capital LLC. The investment committee of Black Canyon Investments LLC possesses the dispositive power with respect to the securities beneficially owned by Black Canyon Investments LLC. The investment committee of Black Canyon Investments LLC is comprised of Messrs. Hooks and Lanigan, and Joshua S. Friedman and Mitchell R. Julis and, therefore, no individual member of the committee is deemed to be the beneficial owner of the securities indirectly owned by Black Canyon Investments LLC. As a manager of Loudon Partners, LLC, Bradley Spencer, chief financial officer of Black Canyon Capital LLC, possesses the voting and dispositive power with respect to the securities beneficially owned by Loudon Partners, LLC.

The principal business of the Black Canyon Affiliates is to make private and public investments. The principal business address of each Reporting Person is 2000 Avenue of the Stars, 11th Floor, Los Angeles, CA 90067.

(d),(e) In the last five years, no Reporting Person has been convicted in a criminal proceeding (excluding traffic violations and similar misdemeanors) or was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Prior to the closing of the Offering on May 27, 2015, each of Black Canyon Direct Investment Fund, L.P., The Canyon Value Realization Fund, L.P., Loudon Partners, LLC, and Mr. Hooks had exchanged 1,296,389, 160,702, 128,897 and 25,136 LLC Units, respectively, for the equivalent number of shares of Class A Common Stock in accordance with the terms of exchange agreements (the “Exchange Agreement”) between the Issuer and holders of LLC Units, and sold such shares in the Offering at a price of $19.05 per share, after deducting underwriting

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discounts and commissions of $0.95 per share. Each of BC-MB GP and The Canyon Value Realization Master Fund, L.P. sold 119,333 and 897,095 shares of Class A Common Stock, respectively, in the Offering at a price of $19.05 per share after deducting underwriting discounts and commissions of $0.95 per share.

Except as otherwise described in this Schedule 13D, none of the Reporting Persons currently has any plans or proposals that would result in or relate to any of the transactions or changes listed in Items 4(a) through 4(j) of Schedule 13D. However, as part of their ongoing evaluation of investment and investment alternatives, the Reporting Persons may consider such matters and, subject to applicable law, may formulate a plan with respect to such matters or make formal proposals to management or the board of directors of the Issuer, other stockholders of the Issuer or other third parties regarding such matters. The Reporting Persons reserve the right to acquire additional securities of the Issuer in the open market, in privately negotiated transactions (which may be with the Issuer or with third parties) or otherwise, to dispose of all or a portion of their holdings of securities of the Issuer or to change their intention with respect to any or all of the matters referred to in this Item 4.

(a) The following table sets forth the aggregate number and percentage of the Class A Common Stock beneficially owned by each Reporting Person (based on 17,858,726 shares of Class A Common Stock outstanding following the closing of the Offering). The aggregate number and percentage of the Class A Common Stock beneficially owned by each Reporting Person is calculated in accordance with Rule 13d-3.

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(b) Mr. Hooks and Mr. Lanigan each have sole voting and dispositive power over the 11,697 stock units granted to each of Mr. Hooks and Mr. Lanigan, which are fully vested and payable in an equivalent number of shares of the Issuer’s Class A Common Stock upon or as soon as practicable, and in all events within 30 days, following the first to occur of (A) the date of separation from service (as defined in the Issuer’s Directors’ Compensation Policy) as a director or (B) the occurrence of a change in control under the Issuer’s Long-Term Incentive Plan.

(c) Except as described above, the Reporting Persons have not effected any transactions in the Class A Common Stock during the period since Amendment No. 2 to the Schedule 13D was filed on April 16, 2015.

(d) No other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Class A Common Stock.

(e) Following the closing of the Offering on May 27, 2015, the Reporting Persons ceased to beneficially own more than five percent of the Class A Common Stock.

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SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: May 27, 2015

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