EASTERN INSURANCEHOLDINGS, INC. ORGANIZED UNDER THE LAWS OF THE COMMONWEALTH OF PENNSYLVANIA

Exhibit 4.1

EASTERN INSURANCE HOLDINGS, INC.

ORGANIZED UNDER THE LAWS OF THE COMMONWEALTH OF PENNSYLVANIA

[SPECIMEN]

is the owner of:

FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK NO PAR VALUE

PER SHARE OF EASTERN INSURANCE HOLDINGS, INC.

a Pennsylvania stock corporation.

The shares represented by this certificate are transferable only on the stock transfer books of Eastern Insurance Holdings, Inc. (the “Company”) by the holder of record hereof, or by his duly authorized attorney or legal representative, upon the surrender of this certificate properly endorsed. This certificate and the shares represented hereby are issued and shall be held subject to all the provisions contained in the Company’s official corporate papers filed with the Department of State of the Commonwealth of Pennsylvania (copies of which are on file with the Transfer Agent), to all of the provisions the holder by acceptance hereof, assents.

This certificate is not valid unless countersigned and registered by the Transfer Agent and Registrar.

IN WITNESS WHEREOF, EASTERN INSURANCE HOLDINGS, INC. has caused this certificate to be executed by the signatures of its duly authorized officers and has caused its corporate seal to be hereunto affixed.

EASTERN INSURANCE HOLDINGS, INC.

The shares represented by this certificate are subject to a limitation contained in the articles of incorporation (the “Articles”) to the effect that for a period of three years after the Company’s initial public offering, no person or entity may acquire more than 10% of the issued and outstanding shares of common stock (“Voting Control”) of the Company. If Voting Control of the corporation is acquired in violation of such limitation, all shares in excess of Voting Control shall be considered from and after the date of acquisition to be “excess shares” and all shares deemed to be excess shares shall no longer be entitled to vote on any matter or to take other shareholder action.

Preferred stock may be issued from time to time as a class without series or, if so determined by the board of directors of the Company, either in whole or in part, in one or more series. The board of directors of the Company has the authority to fix and determine, by resolution, the par value, voting powers, full or limited, or no voting power, and such designations, preferences and relative, participating, optional, or other special rights, if any, and the qualifications, limitations, or restrictions thereof, if any, including specifically, but not limited to, the dividend rights, conversion rights, redemption rights and liquidation preferences, if any, of any wholly unissued series of preferred stock (or the entire class of preferred stock if none of such shares have been issued), the number of shares constituting any such series and the terms and conditions of the issue thereof. The Company will furnish to any shareholder upon request and without charge a full description of each class of stock and any series thereof.

The shares represented by this certificate may not be cumulatively voted in the election of directors of the Company. The Articles also require either (a) the affirmative vote of holders of at least 80% of the issued and outstanding shares of common stock of the Company entitled to vote or (b) the affirmative vote of 80% of the members of the board of directors of the Company and the affirmative vote of holders of at least a majority of the votes which all shareholders of the Company are then entitled to cast to amend provisions of the Articles with respect to shareholders having the right to one vote for each share of common stock; terms and classes of the board of directors; the approval of certain transactions; annual and special meetings; the authority to make, amend, alter, change or repeal the bylaws of the Company; the relevant factors to be considered by the board of the directors in evaluating any offer of another party to engage in certain transactions with the Company; and the prohibition of any person or entity to acquire Voting Control (as defined) of the Company.

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

PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFICATION NUMBER OF ASSIGNEE

                                                                                                       shares of the common stock represented by this certificate and do hereby irrevocably constitute and appoint                                                                                                                           , attorney, to transfer the said stock on the books of the within-named bank with full power of substitution in the premises.