Mass. Gen. Laws ch. 175 § 119C
Upon the death of an insured, the proceeds payable under any policy of individual life insurance which is in force on the date of death shall include the payment of interest at the rate for proceeds left on deposit with the insurer beginning thirty days after the death of the insured and shall not be payable until receipt by the insurer of proof of the insured's death. In the event the insurer does not pay interest on proceeds left on deposit with the insurer, the rate of interest shall be six per cent. If the beneficiary brings an action to enforce such payments and prevails, the court shall award interest in accordance with the provisions of section six C of chapter two hundred and thirty-one, in lieu of any interest payment contained in this section.
Mass. Gen. Laws ch. 175, § 119C