Mass. Gen. Laws ch. 55 § 18G
An independent expenditure or electioneering communication made by an individual, corporation, group, association, labor union or other entity which is transmitted through paid radio, television or internet advertising shall include a statement disclosing the identity of the individual, corporation, group, association, labor union or other entity paying for the advertisement. If the independent expenditure or electioneering communication is a radio or television advertisement, the advertisement shall include a statement by the individual paying for the advertisement in which the person acknowledges paying for the message and identifies that person's city or town of residence. If the radio or television advertisement is paid for by a corporation, group, association or a labor union, the following statement shall be made by the chief executive officer of the corporation, the chairman or principal officer of the group or association or the chief executive or business manager of a labor union: "I am _________________ (name) the ______________________ (office held) of _____________________ (name of corporation, group, association or labor union) and ______________ (name of corporation, group, association or labor union) approves and paid for this message." The statements in television advertisements shall be conveyed by an unobscured, full-screen view of the person making the statement. If an independent expenditure or electioneering communication is transmitted through internet advertising, the statement shall appear in a clearly readable manner with a reasonable degree of color contrast between the background and the printed statement.
An independent expenditure or electioneering communication made by an individual, corporation, group, association, labor union or other entity which is transmitted through paid television, internet advertising or print advertising appearing larger than 15 square inches or direct mail or billboard shall include a written statement at the bottom of the advertisement or mailing that contains the words "Top Contributors" and a written statement that lists the 5 persons or entities or if fewer than 5 persons or entities, all persons or entities that made the largest contributions to that entity, regardless of the purpose for which the funds were given; provided, however, that only contributions in excess of $5,000 reportable pursuant to this chapter during the 12-month period before the date of the advertisement or communication shall be listed. If no such contribution is received by the entity making an independent expenditure or electioneering communication, the advertisement or communication may exclude the statement. The advertisement or communication shall also include a written statement, as specified by the director, at the bottom of the advertisement or communication that directs viewers to the official web address of the office of campaign and political finance. This paragraph shall also apply to advertisements or communications purchased to influence or affect the vote on a question submitted to the voters.
Whoever violates this section shall be punished by imprisonment in the house of correction for not more than 1 year or by a fine of not more than $10,000, or both.
Mass. Gen. Laws ch. 55, § 18G