How Polymarket Works - The Tax-Relevant Mechanics
Polymarket is a prediction market where users buy and sell binary outcome contracts priced between $0 and $1. If you buy a "Yes" share at $0.40 and the market resolves in your favor, the share settles at $1.00 - a $0.60 gain per share. If the market resolves against you, the share expires worthless and your entire position becomes a capital loss. Shares can also be sold at any price before resolution, creating a taxable disposal at the sale price.
All trading happens on Polygon through a proxy wallet that Polymarket creates for each user. This wallet holds your USDC and outcome share tokens on-chain. Because trading happens on-chain, your activity is fully verifiable from public blockchain data - which is how DYOR.tax scans your history without requiring any login or API key.
Polymarket International, which serves most global users, issues no tax forms. There is no 1099-B, no 1099-DA, and no W-2G. Polymarket US (beta, launched November 2025) has not confirmed whether it will issue any forms. Under IRS Notice 2014-21 and subsequent guidance, USDC is treated as property, not cash. Your cost basis is your entry price in USD, and your proceeds are the settlement value or sale price. Every trade, settlement, and secondary sale is a separate taxable event.
How the US Likely Taxes Polymarket Profits
The IRS has issued no specific guidance on prediction market taxation, and the classification of Polymarket activity remains genuinely unsettled. Tax practitioners generally discuss three frameworks, and the one you (with your tax adviser) apply has a significant impact on your bill.
Framework 1: Capital gains (Section 1001) - this is the most common recommendation from US tax practitioners. Under this approach, each outcome share is treated as property. Short-term gains (positions held under one year) are taxed at ordinary income rates of 10-37%. Long-term gains (held over one year) are taxed at 0%, 15%, or 20% depending on your income. Losses offset gains dollar-for-dollar, and up to $3,000 of net capital losses can be carried against ordinary income each year. Gains go on Form 8949 and Schedule D. DYOR.tax calculates your report under this framework.
Framework 2: Section 1256 contracts (60/40 treatment) - Section 1256 applies to certain regulated futures and foreign currency contracts and gives them blended treatment of 60% long-term and 40% short-term regardless of holding period. Some advisers have discussed whether Section 1256 could apply to certain prediction-market contracts traded on CFTC-regulated exchanges, but that treatment is not clearly settled and should not be inferred from an exchange's regulatory or DCM status alone. Polymarket International is not a CFTC-regulated exchange, and this framework generally does not apply to activity there.
Framework 3: Gambling income - Under this approach, Polymarket winnings are reported as gambling income on Schedule 1 (Line 8b) and losses are deductible only if you itemize on Schedule A. This was already less favorable for most traders, and the One Big Beautiful Bill Act makes it worse starting tax year 2026: the Act caps gambling loss deductions at 90% of gambling winnings for 2026 and later tax years, meaning a break-even trader can face phantom taxable income. For tax year 2025 (your return due April 2026), the prior rules still apply - losses remain deductible up to 100% of winnings. A trader who wins $10,000 and loses $10,000 in 2026 can only deduct $9,000, leaving $1,000 taxable. Most practitioners see strong reason to avoid this framework where the capital gains classification is defensible.
The USDC Layer - Crypto Taxes on Top
Polymarket runs on USDC, which the IRS treats as property under Notice 2014-21. This means there is a second layer of potential tax events layered on top of your trading activity that most traders miss entirely.
When you buy USDC from a US exchange with fiat dollars, that purchase is an acquisition of property - not itself taxable. If you swap another cryptocurrency to get USDC (for example, ETH to USDC), that swap is a taxable disposal of your ETH at its fair market value on the date of the swap. Depositing USDC from your main wallet into your Polymarket proxy wallet is a transfer between wallets you control - not a taxable event. Withdrawing USDC back out is similarly just a transfer.
The taxable moment with USDC comes when you sell it back for fiat. If your USDC cost basis is $1.00 and you sell it for $1.00, your gain is zero - which is the normal case. But USDC has briefly depegged in the past, most notably during the March 2023 Silicon Valley Bank weekend when it briefly traded at $0.87. If you sold USDC during a depeg event, you may have a reportable loss. DYOR.tax tracks USDC cost basis and flags disposal events separately from your prediction market trading gains so both legs are accounted for.
What DYOR.tax Calculates from Your Polymarket Data
Scanning your Polymarket proxy wallet gives us the complete on-chain record of your trading activity. Under capital-asset accounting at the lot level, each purchase of a Yes or No share creates a cost basis lot - quantity, acquisition date, and USD cost recorded. When you sell before resolution or hold through settlement, that lot is disposed of at proceeds equal to the sale price or the final payout. The holding period from acquisition to disposal determines whether the gain is short-term or long-term.
The engine identifies every trade, redemption, and settlement, groups the activity back to the market level, and applies FIFO by default to calculate gain or loss per position. For US users, FIFO is the statutory default - HIFO and LIFO can be used when implemented as valid specific identification strategies with adequate records, but are not free-standing alternatives. Open positions are tracked separately and excluded from your taxable gains calculation.
For US filers, the report separates short-term positions (held under one year) from long-term positions (held over one year) because they are taxed at different rates and reported on different parts of Form 8949. USDC disposal events - the gains or losses from buying and selling USDC itself - are calculated as a separate line item so they flow correctly to Schedule D.
The optional History CSV from Polymarket's Portfolio export enriches the wallet scan with deposit and withdrawal data. Without it, coverage is around 72%. With it, coverage increases to around 96%. The CSV is optional but recommended if you had significant deposit or withdrawal activity during the year.
US Filing Requirements for Polymarket
Under the capital gains framework, your Polymarket trading goes on Form 8949. Each settled market and secondary sale is a separate line: description, date acquired, date sold or settled, proceeds, cost basis, and gain or loss. Short-term positions fill Part I; long-term fill Part II. The totals flow to Schedule D, which feeds into your Form 1040. The deadline is April 15 for calendar year filers (April 15, 2026 for tax year 2025).
Under the gambling framework, winnings go on Schedule 1, Line 8b. If you itemize deductions, losses go on Schedule A, Line 16 - deductible up to 100% of winnings for tax year 2025. For tax year 2026 and later, the One Big Beautiful Bill Act caps that deduction at 90% of winnings. If you take the standard deduction, losses are not deductible at all.
FBAR (FinCEN 114) and FATCA (Form 8938) obligations are fact-specific. Under FinCEN Notice 2020-2, an account holding virtual currency is not reportable on the FBAR solely because it holds virtual currency. The real question is whether you held assets through a reportable foreign financial account or custodial structure - not whether an on-chain wallet is itself a foreign account. Form 8938 thresholds are $50,000 for single filers at year-end or $75,000 at any point during the year. Users with foreign custodial accounts or complex cross-border structures should consult a specialist before concluding a filing obligation exists or does not.
Polymarket International issues no 1099 of any kind. Polymarket US (beta) has not yet confirmed its reporting approach. The absence of a form does not reduce your filing obligation.
Common Polymarket Tax Mistakes in the US
- Treating gambling and capital gains as equivalent. Starting tax year 2026, the One Big Beautiful Bill Act caps gambling loss deductions at 90% of winnings - meaning a break-even trader under the gambling framework owes tax despite no net profit. The frameworks are not interchangeable and the choice matters more than ever for 2026 and later.
- Ignoring USDC disposals. Selling USDC back to fiat is a taxable event. If your cost basis deviated from $1.00 at any point - including during depeg events - you have gains or losses to report.
- Assuming Polymarket US beta and Polymarket International have the same tax treatment. Polymarket US is a separate regulated entity operating under a different structure. Whether its contracts could eventually receive different tax treatment is uncertain and should not be assumed. Activity on the International platform is not CFTC-regulated and should be analyzed accordingly.
- Not reporting because there is no 1099. The IRS requires you to report all gains and income regardless of whether a form was issued. Self-reporting from blockchain records is the correct approach.
- Assuming an FBAR obligation based on wallet balance alone. Under FinCEN Notice 2020-2, an account holding virtual currency is not reportable on the FBAR solely because it holds virtual currency. The question is whether you have a reportable foreign financial account or custodial structure - not whether an on-chain wallet is itself a foreign account. Get specialist advice before concluding a filing obligation exists or does not.
Related Resources
For broader context on how the US taxes crypto activity, the US crypto tax calculator covers FIFO cost basis, short-term and long-term rates, and the $3,000 loss cap. The Polymarket and Kalshi tax guide goes deeper on the capital gains vs. gambling vs. Section 1256 analysis across both platforms. For token-level reporting, see the airdrop taxes guide for how similar classification questions apply to airdrop income.
For Polymarket traders in other countries: UK - Canada - Australia - New Zealand - India - South Africa
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