Maryland decouples its pass-through deadline from the federal calendar and layered on significant 2025 tax changes: new top income brackets, a capital gains surtax, and a 3% tax on IT and data services. Its corporate and pass-through extensions also run longer than the federal six months.
Maryland Tax Deadlines at a Glance (2026)
Entity Type | Return Due | Extended Due Date |
|---|---|---|
Individuals (Form 502) | April 15, 2026 | October 15, 2026 |
C Corporations (Form 500) | April 15, 2026 | November 16, 2026 (7-month) |
S Corporations (Form 510/511) | April 15, 2026 | November 16, 2026 (7-month) |
Partnerships (Form 510/511) | April 15, 2026 | October 15, 2026 (6-month) |
The key correction: Form 510 pass-through returns are due April 15, 2026 — the 15th day of the 4th month — not the federal March 16. Extensions then differ by entity: corporations and S corporations get 7 months (to November 16), while partnerships get 6 months (to October 15). There is no single “September” Maryland pass-through extension date.
New 2025 Income Tax Brackets and Surtax
Maryland’s 2025 Budget Reconciliation and Financing Act (HB 352) added two new top brackets — 6.25% on income over $500,000 and 6.5% over $1,000,000 — so the state rate now runs 2% to 6.5%. It also created a 2% capital gains surtax for taxpayers with federal AGI over $350,000 (with primary-residence and retirement-account exceptions). On top of the state rate, every county and Baltimore City levies a local income tax from 2.25% up to 3.30%, filed on the same return.
Corporate Rate, PTE, and the New Tech Tax
The corporate income tax rate is a flat 8.25%. Maryland’s elective pass-through entity tax (Form 511, an annual irrevocable election) is paid at the top state rate plus the lowest local rate (6.50% + 2.25%). A major new obligation: HB 352 imposes a 3% sales-and-use tax on data and IT services (including previously-exempt B2B SaaS), effective July 1, 2025 — a consideration for any firm or client buying or selling software, data, or IT services.
Estimates, Extensions, and Penalties
Individual estimated payments are due April 15, June 15, September 15, 2026, and January 15, 2027. Extensions are automatic if the extension form is filed timely and at least 90% of tax is paid by the original date — Form 502E (individuals, 6 months), 500E (corporations, 7 months), 510/511E (pass-throughs). Interest accrues from the original due date at Maryland’s annually-set statutory rate, plus a late-payment penalty of up to 10%.
CPA Action Steps
File Form 510 pass-through returns in April, not on the federal March date
Apply the new 6.25%/6.5% top brackets and the 2% capital gains surtax for high-income clients
Flag the 3% tech tax for software/IT/data purchases and sales
Note corporate and S-corp extensions run to November 16 (7-month)
Verify current rates and dates against the Comptroller of Maryland (marylandcomptroller.gov) before filing.