Massachusetts Pass-Through Entity Tax (PTET)

Why PTET matters in this state

Massachusetts enacted the Elective Pass-Through Entity Excise under M.G.L. c. 63D §§1–7 in 2021, joining the post-Notice 2020-75 wave. The state's flat 5% individual income tax on most income — combined with the Fair Share 4% surtax on income over $1 million, bringing the top combined rate to 9% — means high-earner pass-through owners have a meaningful federal-deduction arbitrage available against the IRC §164(b)(6) SALT cap. Typical beneficiaries are Boston-metro professional-services partners (law, consulting, finance), S-corp owners with materially Massachusetts-sourced income, and biotech/life-sciences entity owners in the Route 128 corridor. The PTE excise converts the state income tax obligation on flow-through income into a federally deductible business expense under IRS Notice 2020-75. Massachusetts's design differentiator is on the owner-credit side, where the state caps the credit at 90% of the distributive share of excise paid — a structural feature, not a procedural penalty.

Election mechanics

The election is made annually on a timely-filed Form 63D-ELT, filed with Form 355S (S corps), Form 3 (partnerships), or Form 2 (trusts), as applicable, on or before the due date including extensions. Critically, the election cannot be made on an amended return — the original or extended return is the only window. Once made, the election is irrevocable for the tax year and qualified members cannot opt out. Form 355S and Form 3 are generally due March 15 for calendar-year filers; Form 2 is due April 15. The excise rate is 5% on income subject to MA personal income tax at the individual partner, shareholder, or beneficiary level (TIR 22-6).

Owner credit walkthrough

Massachusetts deviates from peer states on the owner-side credit: qualified members receive a 90% credit of their distributive share of the PTE excise paid, not 100%. The credit is refundable — excess credit over tax due is treated as an overpayment. Multi-owner allocation is by distributive share. The 10% non-credit residue is a meaningful gotcha (see trap below).

2026 changes

No material 2026 Massachusetts PTE statutory changes pinned this session — c. 63D §§1–7 and the 5% entity-level excise carry forward unchanged. TIR 22-6 remains the operative interpretive guidance for the excise's mechanics and the 90% credit. The Fair Share 4% surtax interaction with PTE excise sits at the personal-return level rather than the entity level — the entity-level excise remains 5%, and Fair Share continues to apply to high-income owners on the personal Form 1.

Composite-return interaction

MA PTE excise stacks with c. 62B PTE withholding for nonresident members rather than replacing it; the manifest does not pin the precise stacking arithmetic for this session. Practically, for entities with material nonresident-member income, the combined withholding + PTE-excise + composite-return matrix is preparer territory. Form 63D-ELT does not displace Form 1-NR/PY filing obligations for nonresident owners.

§199A QBI interaction

MA PTE excise reduces federal flow-through ordinary income per Notice 2020-75 and therefore the §199A QBI base, by roughly 5% of allocated income before the federal 20% deduction. For non-SSTB owners outside the phaseout, the §199A offset is partial; for SSTB owners inside the phaseout the offset is moot and the PTE excise is unambiguously favorable federally — net of the 10% credit residue.