Professional Sports Bettor Taxes: The 2026 IRS Guide

Are you actually a professional? The Groetzinger test

The Supreme Court's decision in Commissioner v. Groetzinger (1987) still controls. To file as a professional gambler, your betting must be:

• Pursued full-time, or at least as a primary occupation
• Carried on in good faith for the production of income
• Conducted with regularity, continuity, and a profit motive — not sporadic play

Winning one big year is not enough. The IRS looks at hours per week, whether you keep books, whether you have another primary job, how you size and price bets, and whether you improve your methods over time. Weekend +EV bettors with a W-2 day job almost always file as hobbyists, not pros.

Schedule C: reporting winnings and expenses

Professionals report gross winnings as gross receipts on Schedule C, then deduct wagering losses and ordinary-and-necessary business expenses on the same form. This is the key advantage over hobby treatment: you don't need to itemize to deduct losses, and business expenses (not just wagering losses) are allowed.

Do not net winnings and losses on a single line — the IRS wants gross-in, gross-out. That's why a session-level ledger matters: each session is one entry with a stake, a return, and a date.

Self-employment tax (15.3%)

Net Schedule C profit is subject to 15.3% self-employment tax (12.4% Social Security up to the wage base, plus 2.9% Medicare with no cap; an extra 0.9% Additional Medicare kicks in above $200K single / $250K joint). This is the single biggest trade-off vs. hobby filing — and the reason many marginal "pros" are better off staying hobbyists.

You deduct half of SE tax as an above-the-line adjustment on Schedule 1, which softens the hit but does not eliminate it.

The 2026 90% loss cap

Starting with the 2026 tax year, gambling losses are deductible only up to 90% of gambling winnings — for both hobby and professional filers. In practical terms, 10% of gross winnings is taxable even in a break-even or losing year on paper.

For a professional running $1M through the book with $980K in losses (a $20K real profit), the deductible loss is capped at $900K. Taxable Schedule C profit is $100K, not $20K — a devastating result before you even reach SE tax. High-volume arbitrage and matched-betting pros are the most exposed and should model this carefully before doubling down in 2026.

Quarterly estimated payments

W-2G withholding on individual bets rarely covers your full liability. Pros owe quarterly estimated tax (Form 1040-ES) on April 15, June 15, September 15, and January 15. Missing them triggers an underpayment penalty even if you pay in full by April.

Safe harbor: pay 100% of last year's total tax (110% if AGI exceeded $150K) via estimates and withholding, and no penalty applies regardless of what you actually owe.

Deductible expenses for pros

• Subscriptions: odds screens, model providers, syndicate access, statistical services
• Travel to sportsbooks and events, when the primary purpose is placing bets
• Home-office deduction on a dedicated workspace
• Computers, monitors, and internet allocated to betting use
• Professional fees: CPA, tax attorney, entity formation
• Bank and payment-processor fees tied to bankroll movement

These are business expenses, not gambling losses — the 90% cap does not apply to them. Keep receipts and document the business purpose.

State tax pitfalls

Several states (Illinois, Indiana, Massachusetts, Michigan, Ohio, West Virginia, Wisconsin) do not allow itemized gambling-loss deductions on the state return. Hobby bettors in these states owe state tax on gross winnings. Filing as a professional on Schedule C sidesteps this — losses flow through the federal AGI — but the state may still challenge pro status.

See the state sports betting tax guide for the state-by-state breakdown.

Audit-ready record keeping

Under Revenue Procedure 77-29, the IRS expects a contemporaneous session log: date, type of wager, venue/book, amounts wagered, amounts won, and net result. A year-end sportsbook download is corroborating evidence, not a substitute. Tax Court has repeatedly disallowed six-figure loss claims backed only by book-issued summaries (see Mayer, Lutz).

For professionals, the record-keeping bar is higher: books should look like any other small business — income by session, expenses categorized, bank reconciliations, and separation between personal and betting funds (ideally through a dedicated account or LLC).

This article is general information, not tax advice. The professional-gambler determination is fact-specific and the 2026 loss cap has planning implications that vary by state and volume — consult a CPA or tax attorney with gambling-industry experience before filing.