SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 1 )

National General Holdings Corp.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

636220 303

(CUSIP Number)

Michael Karfunkel

c/o National General Holdings Corp.

59 Maiden Lane, 38th Floor

New York, NY 10038

(212) 380-9500

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

July 28, 2015

(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 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 §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 (however, see the Notes).

(Continued on following pages)

(Page 1 of 8 Pages)

EXPLANATORY NOTE

This Amendment No. 1 (the “Amendment No. 1”) amends and supplements the initial Schedule 13D (the “Schedule 13D”), as filed with the Securities and Exchange Commission (the “SEC”) on February 20, 2014, by Michael Karfunkel, Leah Karfunkel and AmTrust International Insurance, Ltd. with respect to the common stock, par value $0.01 per share (the “Common Stock”), of National General Holdings Corp., a Delaware corporation (the “Issuer”). Except as specifically amended and supplemented by this Amendment No. 1, the Schedule 13D remains in full force and effect. Unless otherwise indicated, all capitalized terms used herein shall have the meanings given to them in the Schedule 13D.

Item 2. Identity and Background

Item 2(c) is amended as follows:

“Leah Karfunkel is sole trustee of The Michael Karfunkel 2005 Grantor Retained Annuity Trust (the “GRAT”).” is hereby replaced with “Leah Karfunkel was the sole trustee of The Michael Karfunkel 2005 Grantor Retained Annuity Trust (the “GRAT”). In accordance with the terms of the GRAT, upon its expiration at the end of its 10 year term, the assets of the GRAT were distributed to the Michael Karfunkel Family 2005 Trust (the “Family Trust”). Leah Karfunkel serves as a trustee of the Family Trust. The Family Trust also has a second trustee, Barry Zyskind, who delegated sole and exclusive power to vote, invest or dispose of all shares of Common Stock of the Issuer held by the Family Trust to his co-trustee, Leah Karfunkel.”

Item 2(f) is hereby amended and restated in its entirety as follows:

Except for Max Caviet, Julian Griffiths, Michael Bott, Chris Souter and Jo Spittle, every natural person listed on Schedule I hereto is a citizen of the United States of America. Max Caviet, Julian Griffiths, Michael Bott, Chris Souter and Jo Spittle are citizens of Great Britain.

Schedule I to this Schedule 13D is hereby amended and restated in its entirety in the form attached hereto, which is incorporated by reference.

Item 4. Purpose of Transaction.

Item 4 is hereby amended to add the following paragraph:

The purpose of this filing is to report the distribution of the 32,961,262 shares of Common Stock held by the GRAT to a second trust formed by Michael Karfunkel in 2005, the Family Trust. The GRAT was formed in 2005 with a ten year term. Leah Karfunkel, the wife of Michael Karfunkel, served as sole trustee of the GRAT. In accordance with the terms of the GRAT, at the end of the 10 year term, the assets of the GRAT (including the 32,961,262 shares of Common Stock) were distributed to the Family Trust. Leah Karfunkel serves as a trustee of the Family Trust. The Family Trust also has a second trustee, Barry Zyskind, a director of the Issuer. Mr. Zyskind has delegated sole and exclusive power to vote, invest or dispose of all shares of Common Stock of the Issuer held by the Family Trust to his co-trustee, Leah Karfunkel. Accordingly, Leah Karfunkel has all powers of a sole trustee with respect to the shares of Common Stock of the Issuer held by the Family Trust in the same manner that she had such powers with respect to the shares of Common Stock held by the GRAT.

Item 5. Interest in Securities of the Issuer.

Item 5(a) is hereby amended and restated in its entirety as follows:

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

Item 6 is hereby amended and restated in its entirety as follows:

Barry Zyskind executed a Limited Power of Attorney as authorized by the Family Trust, pursuant to which Mr. Zyskind appointed Leah Karfunkel as attorney-in-fact to exercise sole and exclusive voting, investment and dispositive power over all of the shares of the Issuer’s Common Stock held by the Family Trust.

Item 7. Material to Be Filed as Exhibits.

Exhibit A       Limited Power of Attorney, dated July 28, 2015 executed by Barry D. Zyskind.

SIGNATURE

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.

July 29, 2015

SCHEDULE I

Exhibit A

LIMITED POWER OF ATTORNEY

WHEREAS, Michael Karfunkel (“Grantor”), Leah Karfunkel (“Mrs. Karfunkel”) and Barry Zyskind (“the undersigned,” and together with Mrs. Karfunkel, the “Trustees”) each is a party to a trust agreement, dated as of March 28, 2005 (the “Agreement”); and

WHEREAS, paragraph (E) of clause FIFTH of the Agreement provides that any Trustee may, by revocable power of attorney, delegate to one or more of the co-Trustees then in office the full exercise of all or any powers granted by any provision of the Agreement to the Trustees;

NOW THEREFORE, know all by these presents, that the undersigned hereby makes, constitutes and appoints Mrs. Karfunkel, as the undersigned’s true and lawful attorney-in-fact, with full power and authority as hereinafter described on behalf of and in the name, place and stead of the undersigned to:

(1) exercise sole and exclusive voting power with respect to the assets listed on Schedule A attached hereto;

(2) exercise sole and exclusive investment power, including dispositive power, with respect to the assets listed on Schedule A attached hereto; and

(3) perform any and all other acts which in the discretion of the attorney-in-fact are necessary or desirable for and on behalf of the undersigned in connection with the foregoing.

The undersigned hereby gives and grants the foregoing attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary or appropriate to be done in and about the foregoing matters as fully to all intents and purposes as the undersigned might or could do if present, hereby ratifying all that the attorney-in-fact of, for and on behalf of the undersigned, shall lawfully do or cause to be done by virtue of this Power of Attorney.

This Power of Attorney shall remain in full force and effect and may only be revoked by the undersigned upon 75 days’ prior written and signed notice to the attorney-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 28^th day of July, 2015.

On this 28th day of July, 2015, Barry Zyskind personally appeared before me, and acknowledged that s/he executed the foregoing instrument for the purposes therein contained.

IN WITNESS WHEREOF, I have hereunto set my hand and official seal.

SCHEDULE A