Mass. Gen. Laws ch. 55, § 9B: Joint contributions to be attributed equally to each contributor when unspecified; rules and regulations for joint contributions

Section 9B. (a) Any joint contribution received by a candidate or political committee that does not indicate the amount to be attributed to each contributor may be attributed equally to each contributor; provided, however, that the attribution does not cause a contributor to make a contribution exceeding the limits in section 7A.

(b) The director shall establish reasonable rules and regulations concerning the making of joint contributions and corresponding contributor notification and recordkeeping requirements for candidates and political committees.