Bonus & Windfall

Large one-time income events — year-end bonuses, equity vesting, business sale proceeds, inheritance, real estate gains — create tax planning opportunities and obligations that regular paycheck income doesn’t. The tax treatment of these events isn’t always intuitive, the withholding is frequently insufficient, and the decisions made in the weeks and months around a large income event can meaningfully affect after-tax outcomes. Planning ahead is worth the effort at any size of windfall.

Employer bonuses are taxed as supplemental wages, with federal withholding at 22% for amounts up to $1 million and 37% for amounts above $1 million in a single payment. If your marginal federal rate is 37% (which applies above $731,200 for MFJ), the 22% withholding on a $500,000 bonus creates a $75,000 federal tax underpayment relative to the tax ultimately owed. Adding state income tax withholding that may also be insufficient, the combination can produce a substantial tax liability at filing that surprises recipients who assumed withholding covered their obligation. Quarterly estimated tax payments or withholding adjustments in the year of a large bonus prevent underpayment penalties.

Business sale proceeds have their own tax structure depending on how the sale is structured (asset sale vs. stock sale), what percentage of proceeds represents ordinary income (depreciation recapture, compensation-related payments) versus capital gain, and whether any installment sale treatment is elected to spread recognition over multiple years. At the high end, a $10 million business sale can have tax liability ranging from $2 million to $5 million depending on these structural decisions — the range that professional tax planning can influence is substantial.

Philanthropic strategies — particularly donor-advised fund contributions in the year of a large income event — can be especially powerful because the charitable deduction offsets income in the high-rate year. The full deduction strategy is covered in deductions. For the capital gains dimension of windfall events, see capital gains. The Tax & Wealth pillar covers windfalls as part of comprehensive high-income tax planning.