In accounting, carrying a balance forward means moving an unused amount from one reporting period into the next instead of letting it disappear at year-end. Carried forward accounting shows up in routine bookkeeping, where last period’s ending balances become this period’s opening balances, and in tax, where unused losses, credits, and deductions can offset income in future years under rules that vary by item. The tax side is where the dollars get large, because a single loss year or an oversized credit can shelter income for years or even decades if the carryforward is tracked and used correctly.
The Basic Idea in Bookkeeping
Carryforwards grow out of accrual accounting’s matching principle, which ties expenses to the revenue they helped produce. At the close of a fiscal period, temporary accounts like revenue and expenses are zeroed out, and their net effect flows into a permanent account, usually retained earnings. That ending retained earnings balance becomes the opening balance for the next period.
The same logic runs through the rest of the books. Ending inventory becomes beginning inventory for the next period’s cost-of-goods-sold calculation. The remaining book value of a depreciating asset carries forward as the starting point for next year’s depreciation expense. These transfers keep the balance sheet internally consistent from one period to the next.
Net Operating Loss Carryforwards
A net operating loss (NOL) happens when your allowable deductions exceed your gross income for the year. For losses arising in tax years beginning after December 31, 2017, the carryforward period is indefinite. The loss never expires.1Office of the Law Revision Counsel. 26 USC 172 – Net Operating Loss Deduction
Indefinite is not unlimited. In any given year, a carried-forward NOL can only offset up to 80% of that year’s taxable income, calculated before the NOL deduction. The remaining 20% is fully taxable at the applicable rate.1Office of the Law Revision Counsel. 26 USC 172 – Net Operating Loss Deduction
Whatever cannot be used because of the 80% cap simply rolls to the next year, where the same limit applies again. The practical consequence catches many taxpayers off guard: a company emerging from heavy losses will still owe some federal income tax during every profitable year, even if accumulated losses far exceed current income.
The Section 382 Ownership-Change Trap
If a business with NOL carryforwards undergoes an “ownership change,” Section 382 sharply limits how much of the pre-change loss it can use each year afterward. An ownership change occurs when one or more shareholders holding at least 5% of the stock increase their combined ownership by more than 50 percentage points over a rolling testing period.2Office of the Law Revision Counsel. 26 USC 382 – Limitation on Net Operating Loss Carryforwards and Certain Built-In Losses
Once triggered, the annual amount of pre-change NOL that can be used against taxable income is capped at the fair market value of the company’s stock immediately before the change, multiplied by the IRS’s long-term tax-exempt rate. For ownership changes in mid-2026, that rate is 3.58%.3Internal Revenue Service. Rev. Rul. 2026-7 A loss corporation worth $20 million that undergoes an ownership change at that rate would face an annual limit of roughly $716,000, even if accumulated NOLs total $50 million. Unused portions of the annual limit do carry to the next year and stack on top of the next allowance, but the pace of use slows dramatically.
The rule comes up in mergers, acquisitions, and venture capital raises. A startup that has burned cash and accumulated large NOLs can inadvertently trigger an ownership change through successive fundraising rounds, and by the time profits arrive the losses may be worth far less than expected. Any company sitting on significant NOLs should track cumulative ownership shifts carefully.
Tax Credit Carryforwards
Credits reduce your tax bill dollar for dollar, while deductions only reduce the income on which tax is calculated. A $10,000 credit saves $10,000; a $10,000 deduction at a 21% rate saves $2,100. That makes unused credits especially valuable to carry forward, and each major credit has its own timeline.
General Business Credits
Most business tax credits, including the research and development credit, fall under the general business credit umbrella of Section 38. When the total credit exceeds tax liability for the year, the excess can be carried back one year and forward up to 20 years.4Office of the Law Revision Counsel. 26 USC 39 – Carryback and Carryforward of Unused Credits Credits that go unused beyond 20 years are permanently forfeited, so businesses need to track the vintage of each credit and apply the oldest first.
Foreign Tax Credit
The foreign tax credit, which prevents double taxation on income earned abroad, follows a shorter timeline. Excess foreign taxes can be carried back one year and forward ten years.5eCFR. 26 CFR 1.904-2 – Carryback and Carryover of Unused Foreign Tax Because the credit is calculated separately for different categories of income, carryforwards must be tracked by both category and year of origin.
Adoption Credit
The federal adoption credit is nonrefundable, so any portion exceeding tax liability carries forward for a maximum of five years. Anything left after five years is permanently lost.6Internal Revenue Service. Adoption Credit
Capital Loss Carryforwards
When capital losses exceed capital gains for the year, individuals can deduct only $3,000 of the net loss against ordinary income ($1,500 if married filing separately).7Office of the Law Revision Counsel. 26 USC 1211 – Limitation on Capital Losses
Any net capital loss above the $3,000 cap carries forward. For individuals, there is no expiration date; the loss carries year after year until fully used.8Internal Revenue Service. Topic No. 409 Capital Gains and Losses
Capital losses keep their character when they carry forward. A net short-term loss carries as short-term, a net long-term loss as long-term. That matters because short-term losses offset short-term gains first (taxed at ordinary income rates), while long-term losses offset long-term gains first (taxed at preferential rates). Knowing which type you are carrying affects the actual tax savings.9Office of the Law Revision Counsel. 26 USC 1212 – Capital Loss Carrybacks and Carryovers
State treatment varies. Some states impose stricter time limits or different annual caps, so the federal indefinite carryforward does not automatically apply on a state return.
Charitable Contribution Carryforwards
Individuals and corporations both face annual limits on charitable deductions, and both get a five-year carryforward for amounts above those limits.10Office of the Law Revision Counsel. 26 USC 170 – Charitable, Etc., Contributions and Gifts
For individuals who itemize, the annual limit is generally 60% of adjusted gross income for cash contributions to qualifying public charities, with lower percentages for certain other gifts and organizations. Corporations are capped at 10% of taxable income. Excess contributions carry forward for up to five succeeding tax years on a first-in-first-out basis, then expire.
Starting in 2026, a new floor applies to the individual charitable deduction. Itemizers can only deduct gifts that exceed 0.5% of adjusted gross income, so smaller donations no longer generate a deduction at all, which may reduce the amount reaching the annual ceiling and creating a carryforward in the first place.
One special case: qualified conservation easement contributions by certain farmers, ranchers, and Native Corporations get a 15-year carryforward instead of the standard five.10Office of the Law Revision Counsel. 26 USC 170 – Charitable, Etc., Contributions and Gifts
Excess Business Losses Feeding Into NOLs
Non-corporate taxpayers (individuals, partnerships, and S corporation shareholders) face an extra layer of limitation before the NOL rules apply. Under the excess business loss rule, aggregate business losses above an annual threshold cannot offset non-business income like wages, interest, and dividends. For 2026, the threshold is $256,000 for single filers and $512,000 for joint filers.
Anything above the threshold gets recharacterized as a net operating loss and carried forward under the standard NOL rules, including the 80% limitation. A sole proprietor with $800,000 in business losses and $100,000 in wage income cannot use the full loss in the current year; the excess above the threshold carries forward and faces the same annual cap as any other NOL. The rule was enacted as part of the 2017 tax overhaul and has been extended through 2028.
Basis Carryover in Like-Kind Exchanges
Carryforward accounting also applies to the tax basis of property in certain nonrecognition transactions. The clearest example is a like-kind exchange under Section 1031, where one piece of real property held for investment or business use is swapped for another without triggering an immediate taxable gain.
The basis of the original property carries over to the replacement property. The new basis equals the old basis, decreased by any cash received and adjusted for any gain or loss recognized on the exchange.11Office of the Law Revision Counsel. 26 USC 1031 – Exchange of Real Property Held for Productive Use or Investment
The gain is deferred, not forgiven. When the replacement property is eventually sold in a taxable transaction, the carried-over basis ensures the deferred gain gets recognized. Failing to track basis through a chain of like-kind exchanges is one of the most common compliance errors the IRS flags, and it can lead to substantially overpaying or underpaying tax.12Internal Revenue Service. Like-Kind Exchanges Under IRC Section 1031 The same basis-carryover logic applies to other nonrecognition transactions, including certain corporate reorganizations and insurance policy exchanges under Section 1035.
Keeping Track of Carryforward Balances
The biggest practical risk is losing track of what you have. NOLs with no expiration date are easy to forget. Tax credits with 20-year windows can lapse because no one flagged them. Capital losses from a bad year a decade ago may never make it onto a return prepared by a new accountant who was not handed the prior history.
Every carryforward balance should be documented with its year of origin, original amount, amount used to date, remaining balance, and expiration date if any. Businesses should keep this in a formal tax provision workpaper. For individuals, it should live in the preparer’s permanent file and roll forward in the tax software from year to year.
Changes in tax preparers, accounting systems, or business ownership are the moments when carryforward balances most often get dropped. If you are switching accountants or acquiring a business, requesting a complete carryforward schedule is one of the most valuable things you can do.