SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 4)*

BNC BANCORP

(Name of Issuer)

Common Stock, no par value

(Title of Class of Securities)

05566T101

(CUSIP Number)

EZRA S. BERGER

AQUILINE CAPITAL PARTNERS LLC

535 MADISON AVENUE

NEW YORK, NY 10022

(212) 624-9500

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

Copy to:

MARK J. MENTING, ESQ.

SULLIVAN & CROMWELL LLP

125 BROAD STREET

NEW YORK, NY 10004

(212) 558-4000

June 8, 2012

(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.

(Continued on following pages)

(Page 1 of 2 Pages)

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).

This Amendment No. 4 to Schedule 13D (this “Amendment”) amends and supplements the Statement of Beneficial Ownership on Schedule 13D, filed on June 24, 2010, as amended by the first amendment thereto, filed on April 11, 2011, by the second amendment thereto, filed on April 4, 2012 and by the third amendment thereto, filed on June 4, 2012 (the “Prior Statements”). Capitalized terms used and not defined in this Amendment shall have the meanings set forth in the Prior Statements. Except as specifically provided herein, this Amendment does not modify any of the information previously reported in the Original Statement.

Item 3. Source and Amount of Funds or Other Consideration

The funds used by Aquiline BNC Holdings LLC for the transaction described below were obtained from working capital.

Item 4. Purpose of the Transaction

On June 8, 2012, pursuant to the Securities Purchase Agreement, Aquiline BNC Holdings LLC acquired 21,115 shares of BNC’s Series B-1 Preferred Stock and 4,300 shares of Series C Preferred Stock for an aggregate purchase price of $25,415,000 in cash. Aquiline BNC Holdings LLC’s acquisition of the Series B-1 Preferred Stock and Series C Preferred Stock was part of private placement that totaled $72,500,000.

SIGNATURES

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

Dated: June 8, 2012