#tax-deadlines
Important tax filing deadlines and compliance dates to remember
Irish sole traders filing Form 11 in 2026 face a mid-year PRSI Class S rise from 4.2% to 4.35% on October 1, a €650 minimum PRSI charge, and the preliminary tax rule requiring 100% of prior-year or 90% of current-year liability by October 31 — with a ROS extension to mid-November for those who file and pay online.
Businesses that missed the July 4, 2026 begin-construction deadline can still claim the 30% Section 48E solar credit — but only if the system is placed in service by December 31, 2027, with no partial credit after. Covers the under-1 MW prevailing-wage exemption, domestic content and energy community adders, MACRS plus 100% bonus depreciation, selling the credit under Section 6418, and the 10-year FEOC clawback risk.
After Tropical Storm Arthur struck Louisiana on June 17, 2026, the IRS postponed federal tax deadlines to November 2, 2026 for Avoyelles, St. Landry, St. Tammany, and Terrebonne Parishes under FEMA declaration 4927-DR. The relief covers returns and estimated payments automatically — but not payroll tax deposits or 1099s — and a Section 165(i) election lets storm-damaged businesses claim casualty losses on last year's return.
The IRS pushed most federal tax deadlines for the May 16, 2025 St. Louis tornado (FEMA DR-4877) to November 3, 2025 — but the Section 165(i) election to deduct disaster losses on a 2024 return stays open until October 15, 2026, and penalty-free retirement withdrawals and SBA loans up to $2 million remain in play for affected businesses.
After Super Typhoon Sinlaku struck Saipan, Tinian, Rota, and the Northern Islands on April 11, 2026 (FEMA declaration DR-4910), the IRS postponed filing and payment deadlines falling between April 11 and November 2, 2026 to November 2 — automatically, for any taxpayer with an address of record in the CNMI. Here's what's covered, the April 27 payroll-deposit cutoff that already passed, and the Section 165(i) election that can put a refund in your hands by October 15.
The IRS postponed tax deadlines to August 20, 2026 for Honolulu, Maui, and Kauai counties after the March 2026 Kona Low storms — but Hawaii's separate Form L-115 state relief closes July 20, and SBA loan deadlines fall on August 13, 2026 (physical damage) and January 7, 2027 (EIDL). Here's who qualifies, what's automatic, and the casualty-loss election that can accelerate a refund.
The OBBBA's one-time retroactive Section 174 election for 2022–2024 R&D amortization closed July 6, 2026, but the standard three-year R&D credit window and permanent 2025+ immediate expensing under Section 174A remain available to small businesses.
IFTA returns are due four times a year, and two consecutive missed filings can get an owner-operator's fuel tax license revoked. This guide covers the quarterly deadlines, the $50-or-10% late penalty, the four-year record retention rule, the audit triggers auditors actually look for, and the recordkeeping habits that keep filings painless.
For 2025 tax year returns filed in 2026, the IRS charges partnerships and S-corps $255 per partner or shareholder per month for late Forms 1065 and 1120-S, plus $330 per late Schedule K-1, while a new automatic relief program forgives first-time penalties for taxpayers with three years of clean compliance history.
The IRS payroll tax deposit lookback period runs from July 1 of the second preceding year through June 30 of the prior year; employers reporting $50,000 or less in that window deposit monthly, those above it deposit semiweekly, and accumulating $100,000 or more in liability on a single day triggers a next-day deposit requirement and semiweekly status through the following year.
Late Schedule K-1s are the norm, not the exception — a Form 7004 extension pushes partnership and S-corp returns, and every K-1 tied to them, to September 15, a full five months past the April 15 personal deadline. The fix is a simple playbook, file Form 4868, pay at least 90% of a good-faith estimate, and amend with Form 1040-X once the real numbers arrive.
Indoor tanning services carry a 10% federal excise tax reported quarterly on IRS Form 720 Part II, and salons that don't isolate it in a dedicated liability account and itemize bundled packages are the ones examiners flag.
