Mass. Gen. Laws ch. 170 § 12
Each person who is recorded on the books of the corporation as the holder of 1 or more shares or accounts referred to in chapter 167D shall be deemed a member and shareholder of and depositor in the corporation.
Each member shall be entitled to 1 vote at all shareholders' meetings, subject to the limitations contained in this section and such limitations, if any, as may be contained in the by-laws.
At any meeting, no person who votes in 1 capacity shall be entitled to vote in any other capacity. A co-owner of any shares or accounts who does not vote in any other capacity may vote as the representative of the co-owners. A corporate fiduciary or other corporation or a partnership or association may vote by a person duly authorized, if such person does not otherwise vote; provided, however, a fiduciary, whether individual, corporate or otherwise, may vote on behalf of 1 trust or estate only. No person shall be entitled to vote either as a member or in any representative capacity unless such person shall have attained the age of 18 years. No person shall vote by proxy except as otherwise may be expressly authorized by law.
Mass. Gen. Laws ch. 170, § 12