Year-end timing: closing a big sale in December or January

How it works

For a cash sale, gain is recognized when the sale closes: generally when title and the benefits and burdens of ownership pass, not when the contract is signed. Close on December 30 and the gain is on this year's return; close on January 2 and it is on next year's, with the tax due the following April. On an installment sale, gain follows the payments, so a December closing with a small down payment and the first note payment in January puts most of the gain in later years (IRC 453).

Moving the date matters most when this year's income is high (a final year of salary, a large bonus, other gains) and next year's will be low.

Constructive receipt, escrows and holdbacks

Income is taxed when it is credited to you, set apart for you or otherwise made available so you can draw on it, unless your control is subject to substantial limits (Treas. Reg. 1.451-2(a)). A buyer ready to wire funds in December under a contract calling for a December closing cannot be put off by the seller simply declining the money. Agree on the timing in the purchase agreement, before the money is available.

• Escrow securing a note. If a note is secured directly or indirectly by cash or a cash equivalent, receiving it is treated as receiving payment (Temp. Treas. Reg. 15a.453-1(b)(3)(i)). A cash escrow you can look to for payment does not defer anything.
• Holdbacks. Part of the price held back for indemnity claims, subject to real conditions, is generally taxed when it is released to you, if the sale is reported on the installment method.

Estimated tax: the safe harbor that protects a big-gain year

You avoid the federal underpayment penalty if timely payments cover the lesser of 90% of this year's tax or 100% of last year's tax, raised to 110% if last year's AGI was over $150,000 ($75,000 married filing separately) (IRC 6654(d)(1)). Paying 110% of last year's tax in four installments, then the balance by April 15, keeps the federal penalty away even in a sale year with a much larger tax. The annualized income installment method can lower the required payments when the sale closes late in the year (IRC 6654(d)(2); IRS Publication 505).

California is stricter: if your current-year California AGI is $1,000,000 or more ($500,000 married filing separately), the prior-year safe harbor is not available and estimates must be based on the current year's tax (FTB 2026 Form 540-ES instructions).

IRMAA: the two-year Medicare lookback

Medicare Part B and Part D premiums for a year are set by your modified AGI from two years earlier (20 CFR 418.1115). A 2026 sale sets your 2028 premiums. On the 2026 table, joint MAGI above $750,000 puts each spouse in the top tier: $578.00 a month above the standard amounts, $6,936 a year per person (CMS 2026 fact sheet). Moving the closing a year moves the surcharge a year; only spreading the gain, as an installment sale does, reduces the number of surcharge years. Retiring (work stoppage) is a life-changing event that can support a request to use more recent income, but a one-time capital gain stays in the calculation (20 CFR 418.1205).

Bunching deductions in the sale year

• Charitable gifts. A large gift in the sale year, directly or through a donor-advised fund, is deducted against high-rate income. From 2026, itemized charitable gifts count only above 0.5% of AGI (IRC 170(b)(1)(I)), and in the 37% bracket itemized deductions are trimmed by 2/37 (IRC 68).
• State and local taxes. The 2026 cap of $40,400 shrinks by 30% of MAGI above $505,000, down to $10,000 (IRC 164(b)(7)). In a big sale year most sellers are at the $10,000 floor, so prepaying state tax in December adds little federal benefit.
• Losses. Realize capital losses in the same year as the gain. See tax-loss harvesting.

Changing state residency

If you plan to move to a lower-tax state, the move generally needs to be complete, with a new domicile established, before the sale closes. States tax gain on real estate located in the state regardless of where you live, and some states, including California, can reach installment gain from a sale made while you were a resident even when payments arrive after you leave. See state residency change before a sale.

Worked example

Assumptions (illustrative): married couple filing jointly selling a business for a $1,500,000 long-term gain. In 2026 they have $400,000 of salary; after retiring at the closing, their 2027 income is $80,000. Both years computed on 2026 tables for an apples-to-apples view. Tax caused by the sale, computed with the Big Sale Tax engine (federal income tax, 3.8% net investment income tax and state).

The January closing produces $48,207 less tax in Texas and $63,222 less in California in this example, and the payment is due a year later. Either way, the year of the gain sets Medicare premiums two years later at the top tier for this couple.

Who it fits, and who it does not

Good fit: sellers retiring at the closing, sellers with a one-time high-income year, and sellers moving states. Limited fit: sellers whose income stays high every year, deals where a buyer or lender will not move the date, and sellers expecting higher rates next year.

IRS stance and audit risk

Choosing a closing date is ordinary planning. Audit issues arise when the facts do not match the date: funds available in December but held at the seller's request, an escrow that secures a note, or a residency move that is not real. Keep the contract, settlement statement and escrow instructions consistent.

Costs and fees

There is no product to buy. The costs are deal costs: a buyer may ask for a price concession or an interest adjustment to wait, a rate lock may need extending, and carrying the business or property for a few more weeks has its own expense and risk.

How it compares with a Section 453 installment sale

Moving the closing shifts the whole gain one year. An installment sale spreads gain across as many years as the note runs, which can keep more of it in lower brackets, below the net investment income tax threshold in later years and out of top IRMAA tiers. The two combine well: close in December with a modest down payment and start the note payments in January. Model your dates with the estimator.

Frequently asked questions