Mass. Gen. Laws ch. 176 § 43
If the stated periodical contributions of the members of any society subject to section forty-one are insufficient to pay all reported death, disability, hospitalization and medical service claims in full, and to provide for the creation and maintenance of the funds required by its by-laws or by this chapter, additional contributions or additional, increased or extra rates of contributions shall be collected from its members to meet the deficiency, and the by-laws of the society shall so provide; and such by-laws may provide that upon the written application or consent of the member his certificate may be charged with its proportion of any deficiency disclosed by valuation, with interest not exceeding five per cent per annum.
Mass. Gen. Laws ch. 176, § 43