IRC Sec 270: Hobby Loss Limits, Reporting, and Penalties

The hobby loss rules in Section 183 of the Internal Revenue Code limit what you can deduct when the IRS decides an activity isn’t a real business. You still owe tax on every dollar the activity brings in, but your expense deductions are capped — starting in 2026, at 90% of the activity’s gross income, and only if you itemize. The rules apply to individuals, partnerships, estates, trusts, and S corporations; C corporations are exempt.¹

How the IRS Decides Whether Your Activity Is a Hobby

The question is whether you actually entered the activity to make money. You don’t need a reasonable expectation of profit, but you do need a genuine profit objective backed by how you behave.² No single factor decides it. Treasury regulations list nine that normally come into play:

How you run the activity. Accurate books, a separate bank account, and willingness to change methods when something isn’t working all point toward a profit motive.
Your expertise or your advisors’ expertise. Studying the field and following expert advice helps your case; ignoring that advice hurts it.
Time and effort you invest. Significant hours matter, especially when the work isn’t inherently fun. Hiring qualified staff counts too.
Expected appreciation of assets. Operating losses can still coexist with a profit motive if you reasonably expect assets like land to appreciate enough to produce an overall gain.
Your track record in similar activities. A history of turning unprofitable ventures around strengthens your case, even in a different field.
Income and loss history. Losses that stretch well past a normal startup period look bad; losses caused by outside events like a recession or disaster are less damaging.
Occasional profits. Even small, infrequent profits help. A realistic shot at a large eventual payoff can satisfy this factor on its own.
Your other income. Substantial wages or investment income that hobby losses conveniently offset invites suspicion of a tax shelter. If the activity is your main income, that suspicion fades.
Personal pleasure or recreation. Activities people typically do for fun, like horse breeding, art collecting, or charter fishing, face extra scrutiny. Enjoying the work doesn’t kill a profit motive on its own, but the IRS will look harder at the other eight factors.²

These nine aren’t exclusive, and they aren’t scored. Five favorable factors against four unfavorable doesn’t automatically win. In audit disputes the first factor (businesslike operation) and the last (personal pleasure) tend to carry the most weight, because they’re the hardest to fake.

The Three-Out-of-Five Profit Presumption

Section 183(d) gives you an objective test that shifts the burden of proof. If your activity shows a profit in at least three of five consecutive tax years ending with the current year, the law presumes you’re in it for profit. The IRS can still challenge you, but it now has to prove you lack a profit motive.³

Horse activities get a longer runway. For breeding, training, showing, or racing horses, the presumption applies if the activity shows a profit in at least two of seven consecutive tax years.¹

Form 5213 and the Trade-Off

A new activity won’t have enough years of data for the presumption to apply. Form 5213 lets you elect to postpone the IRS’s determination until the full testing window closes — the fourth tax year after you started for most activities, the sixth for horse activities.⁴

You must file Form 5213 within three years after the due date (without extensions) of your return for the first tax year of the activity. If the IRS sends you written notice proposing to disallow deductions before that three-year window closes, you have 60 days from receiving the notice to file. The 60-day deadline doesn’t extend the three-year period; it’s a secondary trigger, not an extension.⁴

Filing comes with a cost. The postponement buys you time, but it also flags for the IRS that you’re running an activity with current losses and hoping to turn things around. Some tax advisors recommend against filing for that reason, preferring to take the deductions and defend them on the merits if challenged.

How Hobby Deductions Are Limited

When an activity is a hobby, you can’t deduct expenses in whatever order helps you most. Treasury Regulation 1.183-1(b) sets a strict three-tier priority. Each tier gets funded only after the one above it, and the three combined can never exceed the gross income from the activity.⁵

Tier 1 covers deductions you could claim even if the activity didn’t exist, like property taxes or mortgage interest on property used in the hobby. These come off hobby income first, and any excess remains deductible under the normal rules for those items.
Tier 2 covers operating expenses that don’t adjust property basis, like supplies, advertising, and insurance. These are deductible only to the extent hobby income exceeds Tier 1.
Tier 3 covers expenses that adjust basis, like depreciation and amortization. These come last, deductible only to the extent hobby income exceeds Tier 1 and Tier 2 combined.⁵

The ordering decides which expenses disappear entirely when hobby income can’t cover everything. Tier 3 gets squeezed out first, which means you lose the ability to reduce the tax basis of your property. That shows up later as a larger taxable gain when you sell.

What Changed for 2026

From 2018 through 2025, the Tax Cuts and Jobs Act suspended miscellaneous itemized deductions subject to the 2% AGI floor, which is where hobby expenses beyond Tier 1 lived. During that window, hobby expenses were effectively non-deductible, and you owed tax on all hobby income with almost no offset.

The One Big Beautiful Bill Act, signed in 2025, permanently eliminates the general category of miscellaneous itemized deductions subject to the 2% floor. It also adds a new provision just for hobbies: starting in 2026, you can deduct hobby expenses up to 90% of your hobby gross income. The deductible portion goes on Schedule A as a miscellaneous itemized deduction not subject to the 2% floor.

Two consequences follow. First, 10% of your hobby income is always taxable, even if your expenses exceed your income. Second, you have to itemize to get any benefit at all. If you take the standard deduction, your hobby expenses produce zero tax savings, and you owe tax on the full gross income.

How to Report Hobby Income and Expenses

Hobby income goes on Schedule 1 (Form 1040), line 8j, as other income. You report the full amount; there’s no netting of expenses before reporting.⁶ A business, by contrast, would report net income or loss on Schedule C.

Allowable deductions under the 90% cap go on Schedule A. For taxpayers with modest hobby income, the standard deduction often beats itemizing anyway, which means in practice their hobby expenses buy them nothing on the return.

Losses You Can’t Deduct Are Gone

Section 183 applies before the passive activity loss rules of Section 469.³ That ordering kills a common assumption. Once an activity is classified as a hobby, the disallowed losses don’t carry forward under Section 469 or any other provision. They’re permanently non-deductible. They can’t bank against future passive income, offset wages, or reduce investment income.

A concrete example: a hobby that generates $10,000 of income and $15,000 of expenses produces $10,000 of reportable income and up to $9,000 of deductions under the 2026 rules. The remaining $6,000 is gone.

Accuracy Penalties and the Role of Documentation

If you claim full business deductions and the IRS later reclassifies the activity as a hobby, the problem isn’t just the extra tax. Section 6662 allows a 20% accuracy-related penalty on the underpayment if the IRS finds negligence or disregard of the rules.⁷ On a $5,000 underpayment, that’s $1,000 on top of the tax, with interest running from the original due date.

Documentation is the defense against both reclassification and penalties. Keep records that speak directly to the nine regulatory factors: a written business plan, separate financial accounts, logs of time spent, evidence of expert consultations, and a record of adjustments you made when something wasn’t working. Taxpayers who lose hobby loss cases almost always share one thing in common: they couldn’t produce records showing they ran the activity like someone who actually meant to make money.

1
Internal Revenue Service. Is Your Hobby a For-Profit Endeavor?
2
eCFR. 26 CFR 1.183-2 – Activity Not Engaged in for Profit Defined
3
Office of the Law Revision Counsel. 26 USC 183 – Activities Not Engaged in for Profit
4
Internal Revenue Service. Form 5213 – Election to Postpone Determination as to Whether the Presumption Applies That an Activity Is Engaged in for Profit
5
Internal Revenue Service, Treasury. 26 CFR 1.183-1 – Activities Not Engaged in for Profit
6
Taxpayer Advocate Service. Hobby vs. Business Income
7
Internal Revenue Service. Accuracy-Related Penalty