EXHIBIT 3.6

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

ARCH CAPITAL GROUP (U.S.) INC.

The following Amended and Restated Certificate of Incorporation of Arch Capital Group (U.S.) Inc. (the “Corporation”) (i) amends and restates the provisions of the Certificate of Incorporation of Arch Capital Group (U.S.) Inc. originally filed with the Secretary of State of Delaware on March 20, 1995 under the name Risk Capital Re, Inc. and (ii) supersedes the original Certificate of Incorporation and all prior amendments and restatements thereto in their entirety.

1. Name. The name of the Corporation is ARCH CAPITAL GROUP (U.S.) INC.

2. Purposes. The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the Delaware General Corporation Law, as amended from time to time (the “DGCL”).

3. Registered Office. The address of the Corporation’s registered office in the State of Delaware is 1209 Orange Street, City of Wilmington, County of New Castle, Delaware. The name of its registered agent at such address is The Corporation Trust Company.

4. Capital Stock. The total number of shares of capital stock which the Corporation shall have authority to issue is 2,000 shares, consisting of (i) 1,000 shares of common stock, par value $.01 per share (“Common Stock”), and (ii) 1,000 shares of Preferred Stock, par value $.01 per share (“Preferred Stock”). The number of authorized shares of any of the Common Stock or the Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of shares of capital stock of the Corporation representing a majority of the votes represented by all outstanding shares of capital stock of the Corporation entitled to vote thereon, irrespective of the provisions of Section 242(b)(2) of the DGCL, and no vote of the holders of any of the Common Stock or the Preferred Stock voting separately as a class shall be required therefor.

The following is a statement of the designations and the powers, privileges and rights, and the qualifications, limitations or restrictions thereof in respect of each class of capital stock of the Corporation.

A. Common Stock.

The voting, dividend and liquidation rights of the holders of the Common Stock are subject to and qualified by the rights, powers and preferences of the holders of the Preferred Stock set forth herein and as may be designated by resolution of the board of directors of the

Corporation (the “Board of Directors”) with respect to any series of Preferred Stock as authorized herein.

The holders of the Common Stock are entitled to one vote for each share of Common Stock held at all meetings of stockholders (and written actions in lieu of meetings); provided, however, that, except as otherwise required by law, holders of Common Stock, as such, shall not be entitled to vote on any amendment to this Amended and Restated Certificate of Incorporation (including any certificate of designations relating to any series of Preferred Stock) that relates solely to the terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to this Amended and Restated Certificate of Incorporation (including any certificate of designations relating to any series of Preferred Stock) or pursuant to the DGCL. There shall be no cumulative voting.

B. Preferred Stock.

Preferred Stock may be issued from time to time in one or more series, each of such series to consist of such number of shares and to have such terms, rights, powers and preferences, and the qualifications and limitations with respect thereto, as stated or expressed herein and in the resolution or resolutions providing for the issue of such series adopted by the Board of Directors of the Corporation as hereinafter provided.

Authority is hereby expressly granted to the Board of Directors from time to time to issue the Preferred Stock in one or more series, and in connection with the creation of any such series, by resolution or resolutions providing for the issue of the shares thereof, to determine and fix such voting powers, full or limited, or no voting powers, and such designations, preferences and relative participating, optional or other special rights, and qualifications, limitations or restrictions thereof, including, without limitation thereof, dividend rights, special voting rights, conversion rights, redemption privileges and liquidation preferences, as shall be stated and expressed in such resolutions, all to the full extent now or hereafter permitted by the DGCL. Without limiting the generality of the foregoing sentence, and subject to the rights of any series of Preferred Stock then outstanding, the resolutions providing for issuance of any series of Preferred Stock may provide that such series shall be superior or rank equally or be junior to the Preferred Stock of any other series to the extent permitted by law.

5. Board of Directors. The exact number of directors shall be fixed, and may be increased or decreased from time to time in such manner as may be prescribed by the By-Laws of the Corporation. The election of directors need not be by written ballot unless, and to the extent that, the By-Laws so provide.

6. Make, Alter or Repeal By-Laws. In furtherance and not in limitation of the powers conferred by the laws of the State of Delaware, the Board of Directors is expressly authorized to make, alter or repeal the By-Laws of the Corporation.

7. Amendment and/or Repeal of Certificate. The Corporation reserves the right at any time, and from time to time, to amend, alter, change or repeal any provision contained in this Amended and Restated Certificate of Incorporation, and other provisions authorized by the laws of the

State of Delaware at the time in force may be added or inserted, in the manner now or hereafter prescribed by statute; and all rights, preferences and privileges of any nature conferred upon stockholders, directors or any other persons by and pursuant to this Amended and Restated Certificate of Incorporation in its present form or as hereafter amended are granted subject to the rights reserved in this article.

8. Director’s Liability. No director of the Corporation shall be liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except to the extent such exemption from liability or limitation thereof is not permitted under the DGCL as the same exists or may hereafter be amended. Any amendment, modification or repeal of the foregoing sentence shall not adversely affect any right or protection of a director of the Corporation hereunder in respect of any act or omission occurring prior to the time of such amendment, modification or repeal.

9. Indemnification. The Corporation may indemnify, to the full extent permitted by the DGCL and as provided in the By-Laws of the Corporation, any and all persons whom it shall have the power to indemnify from and against any and all expenses, liabilities or other matters.

10. Reorganization. Whenever a compromise or arrangement is proposed between the Corporation and its creditors or any class of them and/or between the Corporation and its stockholders or any class of them, any court of equitable jurisdiction within the State of Delaware may, on the application in a summary way of the Corporation or of any creditor or stockholder thereof or on the application of any receiver or receivers appointed for the Corporation under the provisions of Section 291 of Title 8 of the Delaware Code or on the application of trustees in dissolution or of any receiver or receivers appointed for the Corporation under the provisions of Section 279 of Title 8 of the Delaware Code order a meeting of the creditors or class of creditors, and/or of the stockholders or class of stockholders of the Corporation, as the case may be, to be summoned in such manner as the said court directs. If a majority in number representing three-fourths in value of the creditors or class of creditors, and/or of the stockholders or class of stockholders of the Corporation, as the case may be, agree to any compromise or arrangement and to any reorganization of the Corporation as a consequence of such compromise or arrangement, the said compromise or arrangement and the said reorganization shall, if sanctioned by the court to which the said application has been made, be binding on all the creditors or class of creditors, and/or on all the stockholders or class of stockholders, of the Corporation, as the case may be, and also on the Corporation.

This Amended and Restated Certificate of Incorporation has been duly adopted by the Board of Directors in accordance with the provisions of Sections 242 and 245 of the DGCL.

IN WITNESS WHEREOF, this Amended and Restated Certificate of Incorporation has been duly executed by the undersigned this 24th day of March 2009.

	By:	/s/ Mark Lyons
		Name: Mark Lyons
		Title: President and Chief Executive Officer