Mass. Gen. Laws ch. 160 § 38
Each stockholder shall be entitled to a certificate, which shall be signed by the president and by the treasurer of the corporation, or by such other officers as may be authorized by the by-laws, shall be sealed with its seal, and shall certify the number of shares owned by him in such corporation; but when any such certificate is signed by a transfer agent or transfer clerk and by a registrar and the registrar is not the same person, partnership, association, trust or corporation as the transfer agent or transfer clerk, the signature of the president or of the treasurer or of the other officers authorized by the by-laws, or the seal of the corporation, or any or all of such last-mentioned signatures and such seal upon such certificate may be facsimile, and such certificate shall be as valid and effectual for all purposes as if signed by such president, treasurer or other authorized officer, or sealed with the seal of such corporation, as the case may be.
Mass. Gen. Laws ch. 160, § 38