Tax Readiness: Q1 Tax accounting considerations

2026 Tax Shifts

The One Big Beautiful Bill Act, enacted in mid-2025, has locked in many provisions from the 2017 Tax Cuts and Jobs Act that were due to expire. This includes seven permanent marginal tax rates ranging from 10% to 37%, with inflation-adjusted thresholds pushing the top bracket to $640,601 for singles and $768,701 for joint filers. These changes demand immediate attention in Q1 accounting, as firms must estimate annual effective tax rates incorporating the new landscape.

Corporations and pass-through entities are particularly affected. The revival of 100% bonus depreciation for qualified property allows full expensing in the acquisition year, potentially accelerating deductions but complicating deferred tax assets. Section 179 expensing limits rise to $2.56 million, benefiting smaller operations, yet larger firms grapple with interest limitations and R&D capitalization rules that persist despite calls for repeal.

Individuals see mixed impacts. The standard deduction climbs to $32,200 for joint filers, easing burdens for non-itemizers, while a new $1,000 charitable deduction applies even without itemizing. However, a 0.5% AGI floor on itemized charitable contributions reduces incentives for large donors. The state and local tax deduction cap temporarily jumps to $40,000 but phases down for those earning over $500,000, creating planning pressures in high-tax states.

Stakes are concrete: Q1 estimated tax payments, due April 15, must cover at least 90% of the year's liability or 100% of the prior year's tax to avoid underpayment penalties at 8% annualized interest. Non-compliance could add thousands in costs, as seen in recent IRS audits where mismatches in interim provisions led to adjustments exceeding $10 million for some multinationals. Businesses in sectors like manufacturing face amplified risks from tariff uncertainties intertwined with these reforms.

Non-obvious tensions emerge between federal and state levels. While the OBBBA mandates no state recalculations in some cases, others require additions or subtractions to federal taxable income, leading to divergent effective rates. High-net-worth individuals weigh the benefits of overtime and tip deductions against potential AMT triggers. Pillar Two global minimum tax rules add layers for multinationals, where side-by-side packaging exempts some from mechanisms but demands Q1 disclosures on uncertain tax positions.