You signed a partnership K-1 showing a $200,000 loss. Your tax basis covers it. Your CPA shrugs and deducts the whole thing. The IRS later disallows $150,000 of that loss, sends a bill for back taxes, interest, and penalties, and points to a single form you never filed: Form 6198.
This is the trap that the Section 465 at-risk rules set for partners and S-corporation shareholders who assume that tax basis is the only loss-limitation hurdle. It isn't. The at-risk rules are a separate, parallel test that comes after basis and before passive-loss rules, and they treat your "investment" in a venture very differently from the way subchapter K or subchapter S does. The biggest divergence: nonrecourse debt that boosts your tax basis often gives you zero at-risk amount, and the loss it would otherwise let you deduct gets suspended indefinitely.
If you invest in real estate, oil and gas, equipment leasing, farming, or any operating business through a flow-through entity, this article is the explainer you wish someone had given you before signing the K-1.
The Four-Stage Gauntlet Every Loss Must Survive
Before a single dollar of partnership or S-corp loss reaches your Form 1040, it has to clear four sequential filters, applied in this exact order:
- Basis limitation — Section 704(d) for partnerships, Section 1366(d) for S-corps. Your loss can't exceed your adjusted tax basis in the entity.
- At-risk limitation — Section 465. Your loss can't exceed the amount you have at economic risk in the activity. This is where Form 6198 lives.
- Passive activity loss rules — Section 469. If the activity is passive to you, the loss can only offset passive income.
- Excess business loss limitation — Section 461(l). For 2026, individual business losses above roughly $313,000 (single) or $626,000 (joint) get deferred to next year as a net operating loss.
Each filter is independent. Clearing basis doesn't mean clearing at-risk. Clearing at-risk doesn't mean clearing passive. And even if all three pass, Section 461(l) can still defer the deduction. The amounts blocked at each stage aren't lost — they're suspended and carried forward until you have enough headroom in a future year.
The mistake most taxpayers make is collapsing these into one analysis. They look at the K-1, confirm they have basis, and stop. The IRS doesn't stop there, and neither should you.
What "At-Risk" Actually Means
Section 465 was Congress's response to abusive tax shelters of the 1970s, where investors used nonrecourse loans — debts no one was personally liable for — to claim deductions far larger than their actual cash investment. The fix was simple in concept: you can only deduct losses up to the amount you'd actually lose if the activity went belly-up tomorrow.
Your at-risk amount in a given activity generally includes:
- Cash you contributed to the activity
- Adjusted basis of property you contributed
- Recourse debt of the activity for which you are personally liable
- Qualified nonrecourse financing secured by real property used in holding real property
- Plus your share of activity income, minus prior-year losses already deducted and any distributions
Your at-risk amount does not include:
- Nonrecourse debt where no one is personally liable for repayment
- Amounts protected by guarantees, stop-loss agreements, or insurance that shield you from loss
- Loans from related parties who have an interest in the activity other than as a creditor
- Amounts borrowed from someone with a continuing interest in the activity (the so-called "interested party" rule)
The phrase to internalize is economic exposure. If a creditor can come after your house, your salary, or your other assets when the deal sours, you're at risk. If the only collateral is the activity itself, you generally aren't — with one big real-estate exception.
The Qualified Nonrecourse Financing Carve-Out
Real estate would be functionally dead as an investment class if the at-risk rules took their normal form. Most rental property is financed with nonrecourse mortgages, and treating every dollar of mortgage as "not at risk" would prevent ordinary investors from claiming depreciation losses they're genuinely exposed to.
So Congress carved out "qualified nonrecourse financing" — debt that:
- Is borrowed in connection with holding real property
- Is secured by that real property
- Is borrowed from a qualified lender (banks, government, related parties on commercially reasonable terms) or guaranteed by a government entity
- Is not convertible into equity, and
- For which no person is personally liable for repayment
Note what's missing: this exception only applies to real property used in the activity of holding real property. Equipment, oil and gas, farming, and other operating businesses don't get this carve-out. A nonrecourse equipment loan in a leasing partnership is dead weight for at-risk purposes, no matter how legitimate the financing.
For partnerships, your share of qualified nonrecourse financing is determined by your share of liabilities under Section 752 — generally based on your profit interest, though debt-allocation rules can shift this. Get this allocation right on your K-1, because it directly drives Form 6198.
Six Categories Subject to the Rules
The at-risk rules apply to six categories of activity, but the sixth is so broad it swallows nearly everything:
- Motion picture and videotape production or distribution
- Farming
- Section 1245 property leasing (most tangible personal property leasing)
- Oil and gas exploration or exploitation
- Geothermal deposit exploration or exploitation
- Any other trade or business activity, or activity for the production of income
Category six was added in 1986 and is the reason essentially every operating partnership and S-corp falls under Section 465. The narrow original "shelter" categories still get heightened scrutiny, but the regime is now universal for flow-through losses.
There's one notable exception: real property held before 1987 is grandfathered out of the rules entirely. This rarely matters in practice anymore, but appears in older legacy partnerships and estate-planning structures.
How Form 6198 Calculates Your Limit
You file a separate Form 6198 for each at-risk activity in which you have a loss and any amounts that are not at risk. The form has four parts:
- Part I — Current Year Profit (Loss): Combines all gross income from the activity with all deductions to produce a net figure.
- Part II — Simplified Computation of Amount at Risk: A streamlined version for taxpayers whose at-risk amount only changes due to current-year items.
- Part III — Detailed Computation of Amount at Risk: Used when you need to track the at-risk amount from inception, accounting for prior-year losses, distributions, debt changes, and contributions.
- Part IV — Deductible Loss: The smaller of your current-year loss (Part I) or your at-risk amount (Part II or III). This is what flows to your Schedule E or K-1 input.
Any loss above the at-risk limit is suspended. It carries forward indefinitely, and you can deduct it in a future year when (a) you contribute more cash, (b) you assume more personal liability, (c) the activity generates income that rebuilds your at-risk amount, or (d) you dispose of your interest.
The Recapture Trap
Here's the rule that ambushes the most taxpayers: if your at-risk amount drops below zero during the year — even if the activity has a profit — you must recognize ordinary income up to the amount of your previously deducted losses.
The most common triggers for at-risk recapture are:
- A distribution from the partnership that exceeds your at-risk amount before the distribution
- A change in debt character, especially when recourse debt gets refinanced as nonrecourse, instantly removing it from your at-risk amount
- A reduction in your guarantee or personal liability for activity debt
- A change in your status that adds protection against loss
The recapture amount is capped at your prior-year aggregate at-risk losses, reduced by any prior recapture you've already recognized. But within that cap, it's ordinary income — same character as the losses you originally deducted.
Real-world example: A real estate partnership refinances a recourse construction loan into permanent nonrecourse financing. The partner had been at risk for $500,000 of the recourse debt and had deducted $400,000 of losses against it over three years. The day the loan converts, that $500,000 vanishes from her at-risk amount. If her remaining at-risk balance goes negative by $300,000, she recaptures $300,000 of ordinary income — even though she received no cash and nothing fundamentally changed about her economic position. The IRS doesn't care that the refinance was prudent; the rules trigger on form, not substance.
Why Tax Basis and At-Risk Diverge
Partners often assume basis and at-risk move together. They start that way but diverge fast. Here are the three places they part ways:
Nonrecourse debt allocated under Section 752. A partner's share of nonrecourse partnership debt increases tax basis but generally not at-risk amount (unless the debt is qualified nonrecourse real estate financing). A partner can have $1 million of basis from allocated nonrecourse debt and $0 of at-risk amount from the same debt.
Guarantees and indemnities. If you guarantee partnership debt without right of contribution from other partners, you may pick up at-risk amount even though basis already reflected the underlying debt — or you may not, depending on whether the guarantee is "bottom-dollar" or genuinely shifts economic risk.
Stop-loss arrangements and insurance. Side agreements that protect a partner against loss can preserve tax basis but eliminate at-risk amount, because the partner no longer bears genuine economic exposure.
For S-corporation shareholders the divergence is narrower because shareholder basis doesn't include entity-level debt at all (only direct shareholder loans to the corporation create debt basis). But the at-risk analysis still applies independently and can disallow losses even when debt basis exists.
Aggregation: One Activity or Many?
For at-risk purposes, you calculate a separate amount for each "activity." But what counts as one activity?
The default rule is that each trade or business or income-producing endeavor is its own activity. However, certain activities can be aggregated:
- All leasing of Section 1245 property placed in service in the same tax year by the same partnership can be one activity
- Active participation in an oil and gas working interest aggregates across properties
- Farming activities can be grouped under specific rules
Aggregation matters because at-risk amounts and losses are tracked activity-by-activity. A positive at-risk amount in one activity cannot soak up a loss from a different activity, no matter how related they look operationally. This is the opposite of basis, where partnership-wide basis pools by entity.
The mismatch between Section 465 activity definitions and Section 469 passive activity grouping is one of the trickiest areas in subchapter K practice. The grouping you make for passive purposes (Reg. 1.469-4) is not automatically valid for at-risk purposes, and vice versa.
Three Mistakes Practitioners See Constantly
Mistake 1: Treating nonrecourse equipment debt as at-risk. Operating partnerships financing trucks, equipment, or non-real-property assets with nonrecourse debt routinely confuse this with the real estate carve-out. It isn't. The qualified nonrecourse financing rule applies only to real property used in holding real property.
Mistake 2: Failing to track suspended losses. Losses disallowed under Section 465 do not vanish — they carry forward indefinitely. But they must be tracked per activity, per year, and matched against the right at-risk amounts when they unlock. Without disciplined records, taxpayers either lose the deduction permanently or get audited when they later release suspended losses without basis to back them up.
Mistake 3: Missing recapture on refinances and distributions. Many tax preparers know to check basis on a partnership distribution but forget the parallel at-risk check. A distribution that brings at-risk below zero generates immediate ordinary income recapture, even with no cash gain anywhere in the structure.
Why Good Records Matter More Than the Form Itself
Form 6198 is mechanically simple. The hard part is having the data to fill it in correctly: every contribution, every distribution, every loss already deducted, every change in debt character, every guarantee added or released, every year you owned the interest. The form runs cumulatively from inception.
If you've ever inherited a partnership interest, bought one in the secondary market, or restructured an entity, reconstructing the at-risk history can take days of forensic accounting. Maintaining a contemporaneous at-risk ledger from year one — alongside your basis ledger — is one of those small disciplines that pays off enormously when a CP2000 notice shows up or when you finally dispose of the interest and need to release suspended losses.
Plain-text accounting systems are particularly well-suited to this kind of long-horizon tracking, because the books are version-controlled, auditable, and queryable across decades without depending on a vendor's data-export format. When the IRS asks for your 2009 at-risk computation in 2026, "I can run a query" beats "let me see if I still have a license for that software."
Planning Around the At-Risk Limit
If you find yourself with disallowed losses you'd like to deduct, the legitimate ways to increase at-risk amount are:
- Contribute additional cash or property to the activity
- Convert nonrecourse debt to recourse, where commercially feasible and economically real
- Guarantee activity debt in a way that genuinely shifts economic risk to you (be careful — bottom-dollar guarantees don't count)
- Generate income in the activity that rebuilds your at-risk balance before recognizing further losses
- Dispose of the interest in a taxable transaction, which releases all suspended at-risk losses against the gain
What does not work: paper restructurings designed to make debt look recourse on the form while side agreements preserve nonrecourse economics. The IRS and the courts look through these arrangements consistently, and Section 465(b)(4)'s "protected against loss" rule is broad enough to catch most workarounds.
Keep Your Loss Limitations Straight from Day One
Section 465 is one of four overlapping loss-limitation regimes, and its records have to survive for the life of the activity — sometimes decades. Whether you're tracking basis, at-risk, passive activity status, or excess business loss, the bookkeeping discipline is the same: capture every contribution, distribution, debt change, and loss as it happens, so that when the form has to be filed, the answer is a query rather than an archaeology project. Beancount.io gives you plain-text accounting that's transparent, version-controlled, and AI-ready — so your partnership records remain auditable a decade after the entity dissolves. Get started for free and see why developers and finance professionals are switching to plain-text accounting.