Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 63D, § 4

The excise under this chapter shall be in addition to, and not in lieu of, any other Massachusetts tax required to be paid, including tax imposed by chapter 62 or chapter 63. The excise under this chapter shall be due and payable on the eligible pass-through entity’s original, timely-filed return. A return that reports the excise shall be due at the same time as a partnership information return or corporate excise return would be due for the entity under chapter 62C. Nothing in this chapter shall alter any filing requirements for a qualified member under said chapter 62C.