Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 65A, § 2

The tax imposed by this chapter shall become due and payable at the expiration of twelve months from the date of death, and executors, administrators, trustees, grantees, donees, beneficiaries and surviving joint owners shall be and remain liable for the tax until it is paid. If the tax is not paid when due, interest shall be charged and collected pursuant to section thirty-two of chapter sixty-two C. The commissioner may, for cause shown, extend the time for payment with interest.