[FACE OF CERTIFICATE] ARCH CAPITAL GROUP LTD., an exempted company with limited liability registered under the laws of Bermuda 8.00% NON-CUMULATIVE PREFERRED SHARES, SERIES A, US$0.01 par value per share

Exhibit 4.2

[FACE OF CERTIFICATE]

ARCH CAPITAL GROUP LTD.,

an exempted company with limited liability

registered under the laws of Bermuda

8.00% NON-CUMULATIVE PREFERRED SHARES, SERIES A,

US$0.01 par value per share

This Certifies that SPECIMEN is the registered owner of SPECIMEN FULLY PAID 8.00% NON-CUMULATIVE PREFERRED SHARES, SERIES A, US$0.01 par value per share (“Shares”), of ARCH CAPITAL GROUP LTD., an exempted company with limited liability registerred under the laws of Bermuda (the “Company”), transferable on the books of the Company by the holder hereof in person or by duly authorized attorney upon surrender of this Certificate properly endorsed. This Certificate and the Shares represented hereby are issued under and shall be subject to all the provisions of the Bye-L aws of the Company and the Certificate of Designations relating thereto approved by the Board of Directors (or an authorized committee thereof) of the Company and any amendments thereto, copies of which are on file with the Transfer Agent, to all of which the holder by acceptance hereof assents. This Certificate is not valid until countersigned and registered by the Transfer Agent and Registrar.

WITNESS the seal of the Company and the facsimile signatures of its secretary and a duly authorized officer.

[REVERSE OF CERTIFICATE]

The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations:

Additional abbreviations may also be used though not in the above list.

For Value Received,                                            hereby sell, assign and transfer unto                            &nb sp;                                                    [                                                                 ] (Please insert social security number or other identifying number of assignee and print or typewrite name and address including postal code of assignee)

                                                                                            Shares represented by the within Certificate, and do hereby irrevocably constitute and appoint

 &nb sp;                                                                                         Attorney to transfer the said Shares on the books of the within named Company with full power of substitution in the premises.