Holding an asset for one extra day can change the tax rate on your profit substantially, because gains are taxed on two entirely different schedules depending on the holding period. Understanding where the line falls — and how losses interact with gains — is most of what determines the after-tax result. This guide covers the thresholds, the day-count rule, and the wash sale trap.
Short-term versus long-term
Short-term gains come from assets held one year or less and are taxed at your ordinary income marginal rate — the same brackets as wages.
Long-term gains come from assets held more than one year and are taxed at preferential rates, which for most filers are 0%, 15% or 20% depending on taxable income. Higher earners may also owe the 3.8% net investment income tax, and collectibles and certain real estate carry their own rates.
The practical difference is large. An asset sold for a $10,000 gain:
| Holding period | Applicable rate | Tax on $10,000 gain |
|---|---|---|
| 11 months | Ordinary income (say 32%) | $3,200 |
| 13 months | Long-term (say 15%) | $1,500 |
In that scenario, waiting about two months kept an extra $1,700. This is the clearest illustration of why the holding period deserves attention — and why selling just before the one-year mark is often the worst possible timing.
Model your own situation with the Capital Gains Tax Calculator.
How the year is counted
The holding period begins the day after acquisition and includes the date of disposal. Practically, this means you need to hold through the same calendar date in the following year plus one day: buying on 15 March 2026 makes the gain long-term if sold on 16 March 2027 or later. Selling on 15 March 2027 is short-term, despite feeling like “a year.”
Note that different lot acquisitions have their own clocks. If you bought shares on several dates and sell only part of the position, which lots are sold determines the holding period — and many brokers default to FIFO (first in, first out) unless you specify otherwise at the time of sale. Selecting specific lots before selling can materially change the tax outcome.
Offsetting losses
Losses offset gains, and the ordering is prescribed: short-term losses first offset short-term gains, and long-term losses first offset long-term gains, with any remainder applied to the other category. This matters because it means a short-term loss is most valuable against short-term gains taxed at your highest rate.
If losses exceed gains overall, up to $3,000 of the excess can be deducted against ordinary income each year ($1,500 if married filing separately), with the remainder carried forward indefinitely. That carryforward is genuinely valuable — it does not expire.
The wash sale rule
Selling at a loss to claim the deduction, then buying the same or a substantially identical asset back, triggers the wash sale rule: the loss is disallowed for that sale. The disallowed amount is instead added to the cost basis of the new position, so the tax benefit is deferred rather than destroyed — but you do not get the deduction in the year you expected.
The window is 30 days before or after the sale — 61 days in total — and it applies across your accounts, including a spouse’s and an IRA in some circumstances. Buying a different fund tracking a different index is generally fine; buying the same fund or an equivalent one is not. This rule is easy to trip over in tax-loss harvesting, particularly with automatic dividend reinvestment, which can quietly repurchase shares inside the window.
The 0% bracket and state taxes
The long-term rate structure includes a 0% bracket: filers whose taxable income falls below the threshold pay nothing on long-term gains. This is genuinely useful and widely overlooked — it means that someone in a low-income year (between jobs, early retirement, or deliberately keeping income low) can realise gains tax-free by staying under the threshold.
The threshold is measured against taxable income, which includes the gain itself. So realising a large gain can push part of it into the 15% band: the portion below the threshold is taxed at 0% and only the excess at 15%. This is not an all-or-nothing cliff, which makes partial realisation across tax years a legitimate planning tool.
State treatment is separate and varies widely. Some states have no income tax, some tax capital gains as ordinary income at their own rates, and a few offer partial exclusions. A federal 0% rate does not imply zero state tax, and the difference can be several percentage points — enough to matter on a large gain. Check your state’s treatment before assuming the federal bracket tells the whole story.
Key Takeaways
Long-term gains (held more than one year) are taxed at preferential 0/15/20% rates, while short-term gains are taxed as ordinary income — on a $10,000 gain the difference can exceed $1,700. The clock starts the day after purchase and includes the sale date, so you must hold to the same date next year plus one day. Harvest losses carefully: the wash sale rule disallows losses when you repurchase a substantially identical asset within 30 days either side.