25.4 Loss Limits: Basis, At-Risk, and Passive Rules

The Four-Hurdle Loss Model

Loss limitations are sequential - the taxpayer does not pick the friendliest rule. A business loss must clear each hurdle before reducing current taxable income.

For 2026 the Sec. 461(l) excess-business-loss cap is roughly $313,000 single / $626,000 married filing jointly (inflation-indexed); excess noncorporate business loss converts to a net operating loss carryforward.

Basis Comes First

For partnerships, basis is outside basis: contributions, plus income, minus losses and distributions, adjusted for the Sec. 752 share of liabilities. Recourse liabilities follow economic risk of loss; nonrecourse liabilities are allocated by profit-sharing with special minimum-gain rules.

For S corporations, the shareholder tracks stock basis and debt basis separately. Stock basis rises with contributions and income, then falls with distributions and losses (distributions reduce basis before losses). Debt basis arises only from a direct loan from the shareholder to the corporation. A guarantee of a bank loan to the corporation creates no basis unless the shareholder actually pays and becomes the creditor in substance.

A loss blocked by the basis limit is suspended and revives when basis is restored - through income, contributions, a direct shareholder loan (S corp), or a liability increase (partnership).

At-Risk Is Economic Exposure

Section 465 asks whether the taxpayer truly stands to lose money. Amounts at risk include cash contributed, the adjusted basis of contributed property, and debt for which the taxpayer is personally liable. Qualified nonrecourse financing secured by real property (from a commercial lender or government, not the seller/promoter) counts in real estate. Stop-loss arrangements and guarantees without payment generally fail the at-risk test.

The basis-versus-at-risk gap is a classic simulation trap: a partner may have outside basis from allocated nonrecourse debt yet not be at risk for it (unless it is qualified nonrecourse real estate financing). So basis may allow a loss while at-risk suspends it.

Worked example. A limited partner contributes 20,000 cash and is allocated 30,000 of nonrecourse debt that is not qualified. Outside basis is 50,000, but the at-risk amount is only 20,000. A 35,000 loss is fully allowed by basis but limited to 20,000 by the at-risk rule; 15,000 is suspended under Sec. 465.

Passive Activity Rules and Workflow

After basis and at-risk, apply Section 469. Passive losses generally offset only passive income. A passive activity is a trade or business in which the taxpayer does not materially participate. Rental real estate is passive by default, even with participation, unless a real estate professional exception or the $25,000 active-participation allowance (phasing out between $100,000-$150,000 modified AGI) applies.

Material participation is factual - hours (e.g., the 500-hour test), management role, or regular, continuous, substantial involvement. Limited partners and pure investors usually fail. Portfolio income (interest, dividends, royalties) is not passive income, so it cannot absorb passive losses. Suspended passive losses carry forward and free up when there is passive income or a fully taxable disposition of the entire activity to an unrelated party.

Workflow: (1) compute beginning and current-year basis; (2) reduce for distributions before losses where required; (3) stop the loss at the basis ceiling; (4) test the remainder under at-risk; (5) classify the activity passive vs. nonpassive; (6) track each suspended layer by the rule that suspended it. Never jump to Sec. 469 first - a loss can die at the basis or at-risk hurdle before passive rules ever apply.

Tracking Suspended Losses by Hurdle

The single most tested judgment in this area is labeling which rule suspended a loss, because the rule determines how and when the loss frees up. A loss suspended for lack of basis revives the moment basis is restored - new contributions, current-year income, a direct S-corp shareholder loan, or a Sec. 752 liability increase. A loss suspended by the at-risk rule revives when the taxpayer's amount at risk increases, for example by paying down personally guaranteed debt or contributing more cash. A loss suspended by the passive rule revives only with passive income or a fully taxable disposition.

Integrated worked example. An S corporation shareholder begins with stock basis 10,000 and debt basis 0. The corporation allocates a 25,000 ordinary loss. Basis (10,000) limits the deduction to 10,000; 15,000 is suspended for lack of basis. The next year the shareholder makes a direct loan of 20,000 to the corporation, creating 20,000 of debt basis - the prior 15,000 suspended loss now becomes deductible (subject to at-risk and passive tests).

Contrast the partnership trap. Had this been a partnership, a share of partnership liabilities would have given the partner outside basis directly under Sec. 752, with no need for a personal loan. That structural difference - S-corp debt basis requires a direct loan, while partnership debt automatically adds outside basis - is one of the highest-frequency REG distinctions, and it explains why an identical economic loss may be deductible in a partnership but suspended in an S corporation.

Exam discipline: on a TBS, maintain a running basis schedule, then a separate at-risk schedule, then a passive bucket. Carry each suspended amount forward in its own column. Examiners deliberately give multi-year fact patterns so that the year-two release event only works if you correctly tagged the year-one suspension.