Mass. Gen. Laws ch. 157, § 5: Investment of reserve fund

Section 5. At any regular meeting, or at any duly called special meeting, at which a majority of its stockholders are present, a corporation formed under section three may authorize the investment if its reserve fund or any part thereof, first, in the building where it is doing business, or, second, in a first mortgage of real estate owned and occupied as a dwelling by any of its stockholders.