The 2026 Gambling Loss Cap: How OBBBA Can Tax You on Money You Never Made

If a prediction-market platform, sportsbook, or casino classifies your activity as gambling for tax purposes, a rule change starting in the 2026 tax year makes that treatment more expensive: only 90% of your losses can be deducted, so a break-even year can leave you with taxable income. This post shows the numbers.

What was the rule before 2026?

Under Section 165(d), gambling losses have always been deductible only up to the amount of your gambling winnings, and only if you itemize deductions on Schedule A. If you take the standard deduction, gambling losses aren’t deductible at all, meaning you’re taxed on your gross winnings with no offset. That part hasn’t changed. What changed is what happens even if you do itemize.

What does OBBBA change from 2026?

The One Big Beautiful Bill Act adds a new cap: itemizers can now deduct only 90% of their gambling losses, not 100%, even when losses don’t exceed winnings. That 10% haircut sounds small until you run the numbers on a breakeven year.

How can a break-even year create taxable income?

Say you won $100,000 gambling in 2026 and lost $100,000 gambling in 2026, a wash economically. Under the new cap, itemizing:

You broke even. You still owe tax on $10,000 of income that never existed: the mechanical result of the 90% cap applied to anyone who itemizes and has losses close to their winnings, which describes a lot of active traders in a volatile year.

How do the 90% rule and the winnings cap stack?

There was a real question about how the two limits interact: do you take 90% of losses first and then cap at winnings, or cap at winnings first and then take 90%? They give the same answer when your losses are at or below your winnings, but they diverge once losses run higher. The IRS proposed regulations (REG-113229-25) settle it: apply the 90% to your losses first, then cap the deduction at your winnings. Those regulations are proposed rather than final, so it could still shift, but that is the order WagerMints uses, and it shows the arithmetic so you can check it.

Why is gambling treatment usually the most expensive?

Compare this to the other three methods covered in our overview post. Under capital gains or ordinary income treatment, that same breakeven year owes tax on approximately $0: gains and losses just net against each other, no cap, no haircut. Under gambling treatment with the 2026 cap, the exact same trading activity produces $10,000 of phantom taxable income. If your activity could reasonably be characterized more than one way, and for most prediction-market trading it genuinely can, this is the gap that makes checking all four methods worth the ten minutes it takes, rather than defaulting to whatever a platform’s tax summary happens to assume.

What if you don’t itemize?

None of this is a new discount: it’s a cap on a deduction you get only by itemizing in the first place. If you take the standard deduction, gambling losses remain fully non-deductible, cap or no cap, and you’re taxed on 100% of your gross winnings regardless of how much you lost. The 90% cap only makes a bad situation for itemizers a little closer to the situation non-itemizers were already in.

Want your own numbers? The free 2026 gambling loss calculator shows what you can deduct and how much gambling adds to your taxable income, under the old rules and the new.