Polymarket Tax Guide 2026: Polymarket US and the International App

Polymarket US: what you get and what to keep

Polymarket US is a CFTC-regulated designated contract market (DCM) and derivatives clearing organization (DCO), which Polymarket gained through its July 2025 acquisition of QCEX. You fund it in US dollars by debit card, ACH or wire. It is custodial: your cash sits in your account at its clearinghouse, and withdrawals are free. There is no wallet history to reconstruct — every figure you need is already in US dollars.

Not confirmed. Polymarket US's participant agreement only says you consent to receiving tax forms electronically, “including, without limitation, IRS Form 1099-B”, and its help docs have no tax page (re-checked October 5, 2026). Whether it issues a Form 1099 for event-contract profits is not confirmed, so plan to build your return from your own records.

Records to keep

• Keep every trade confirmation and account statement the app provides, for every year you trade. Those are the starting point for your return.
• Polymarket US documents API endpoints that export your trades, positions, fees and cash ledger as CSV (ledger history starts May 1, 2026). Use them alongside the app's statements and confirmations, not instead of them.

How reporting works

Polymarket US, like Kalshi, is a CFTC designated contract market, so the same open question applies to its contracts: whether they are Section 1256 contracts. The IRS has issued no specific guidance on event contracts, and this guide does not say either treatment is correct. The Kalshi tax guide sets out both positions:

• If a tax professional concludes Section 1256 applies: the net result goes on Form 6781 and is split 60% long-term / 40% short-term. See Section 1256 and the 60/40 rule and Filing: Form 6781, Form 8949, Schedule 1.
• If you instead treat the results as ordinary capital gains: each contract (or a summary attached to the return) goes on Form 8949, the totals flow to Schedule D, and the holding period decides short-term vs long-term. See Short-term vs long-term treatment.

Either way, get a written opinion from a CPA or tax attorney before filing on either basis.

Polymarket’s international app (USDC)

Everything from here to the comparison table is about Polymarket’s international app (polymarket.com), where trades settle in USDC on Polygon. US residents can only close existing positions there; they cannot open new ones.

Why the international app issues no 1099

Polymarket (Polymarket Ltd) is incorporated outside the United States and, for most of its operating history, has not offered its services to US persons through the primary interface. Because it has not been a US broker or US payer for purposes of IRC §6045 and §6041, it has had no legal obligation to issue US Form 1099 to users. The result: US persons who have traded on Polymarket have always been responsible for constructing and reporting their own tax records.

Polymarket US, the CFTC-regulated venue, is a separate product with its own records — see Polymarket US: what you get and what to keep. This part of the guide covers the self-reporting burden for USDC-settled activity on the international app.

If you are a US person who has traded on Polymarket’s international app:

• You must self-report every realized gain and loss on Form 8949 and Schedule D.
• You must determine cost basis for each position in USD terms, even though the contracts are denominated in USDC.
• You may have additional foreign-account reporting obligations (FBAR, Form 8938) if balances cross the applicable thresholds.

USDC tax treatment and cost-basis rules

The IRS classifies virtual currency — including stablecoins like USDC — as property for federal tax purposes. That classification has three practical consequences for Polymarket traders:

1. Every USDC disposition is a taxable event. Using USDC to purchase a Polymarket share is, strictly, a disposition of USDC (property) in exchange for another asset (the share). However, because USDC maintains a ~$1.00 peg, realized gain or loss from the USDC leg is near zero. Most filers treat the USDC basis as unchanging through the Polymarket trade cycle.
2. Gas fees reduce basis. Polygon network gas paid in native MATIC tokens is deductible as a transaction cost, either as an addition to cost basis (on entry) or a reduction in proceeds (on exit).
3. Wallet-to-wallet transfers are not taxable. Moving USDC between wallets you control is not a disposition. Only trading USDC for a different token, contract share, or settlement proceeds triggers a taxable event.

Cost basis for a Polymarket position

Your cost basis in USD for each Polymarket contract is:

• USDC paid at entry, converted to USD at the exchange rate on the entry date; plus
• MATIC gas fees paid at entry, converted to USD at that day's rate.

Your proceeds when the contract resolves are:

• USDC received at settlement, converted to USD at that day's rate; less
• MATIC gas fees paid at exit.

Because USDC is pegged to the dollar within a narrow band, using a flat 1:1 USDC→USD conversion is a defensible simplification used by most tax software. Keep the supporting wallet records in case of audit.

Capital gains vs ordinary income

For a trader who holds a Polymarket position as an investment and resolves it at contract expiry, the resulting gain or loss is capital gain or loss:

• Short-term — held one year or less. Taxed at ordinary income rates (up to 37% federal for 2026).
• Long-term — held more than one year. Taxed at preferential rates (0%, 15%, or 20%).

Almost all Polymarket contracts resolve within days or weeks of creation. Practically, nearly all Polymarket PnL is short-term capital gain taxed at ordinary income rates. Do not assume Kalshi is different: Section 1256 treatment of event contracts is unsettled, and Kalshi has not been verified as treating or reporting its event contracts as Section 1256 contracts.

Trader vs investor status

If Polymarket is your primary livelihood — you trade substantial volume daily, derive the majority of your income from it, and maintain it as a business — you may qualify as a "trader in securities" and potentially elect §475(f) mark-to-market treatment. That is a high bar; casual traders do not qualify. If you believe you might, consult a tax professional — the election must be timely made and is generally irrevocable.

Self-employment tax

Capital gains are not subject to self-employment (SECA) tax. Even if you trade Polymarket full-time, PnL reported on Schedule D does not attract the additional 15.3% Social Security / Medicare levy that applies to trade-or-business income.

Foreign-platform exposure: FBAR and Form 8938

The fact that the international app is a non-US platform matters for more than just 1099 absence. Two separate reporting regimes may apply to US persons holding material balances:

FBAR (FinCEN Form 114)

A US person must file FBAR if the aggregate maximum value of their foreign financial accounts exceeds $10,000 at any point during the calendar year. The threshold is cumulative across all foreign accounts, not per account. FBAR is filed separately from your tax return with FinCEN by April 15 (automatic extension to October 15).

Whether self-custodied USDC used on Polymarket constitutes a "foreign financial account" is unsettled. FinCEN proposed in 2020 to bring self-hosted crypto wallets within the FBAR framework but did not finalize the rule. Most practitioners currently treat self-custodied wallets as outside the FBAR scope — but centralized-exchange accounts at non-US exchanges (including any Polymarket centralized deposit layer) are generally in scope. Conservative practice: if your combined foreign financial accounts and self-custodied foreign balances exceed $10,000 at any point in the year, consult a tax professional about filing a protective FBAR.

Form 8938 (Statement of Specified Foreign Financial Assets)

IRC §6038D requires US persons to file Form 8938 with their annual income tax return if their "specified foreign financial assets" exceed these thresholds:

• Single filers living in the US: $50,000 end-of-year or $75,000 any time during the year.
• Joint filers living in the US: $100,000 / $150,000.
• Filers living abroad: thresholds are higher — $200,000 / $300,000 (single) and $400,000 / $600,000 (joint).

Unlike FBAR, Form 8938 penalties attach to the income tax return and can reach $10,000 per failure plus continuing penalties. As with FBAR, the treatment of self-custodied crypto is ambiguous and a centralized Polymarket deposit account is more clearly in scope than a pure self-custody wallet. Err on the side of disclosure when crossing the thresholds.

Practical red line

If your Polymarket and related foreign-platform balances cross $10,000 at any point in the year, treat foreign-account reporting as an active question to raise with your CPA. The cost of filing a protective FBAR is trivial; the penalty for a missed willful FBAR is up to 50% of the unreported account balance, per year.

Step-by-step: how to self-report

1. Identify every Polygon wallet you used with Polymarket. This includes the primary Polymarket-connected wallet and any other wallet you funded or deposited through. You need the complete list before you begin.
2. Export wallet activity. Pull the full transaction history for each wallet from Polygonscan, or import the wallet into a crypto tax tool. Most tools (Koinly, CoinTracker, ZenLedger, TokenTax) support read-only wallet address imports in seconds.
3. Tag Polymarket contract transactions. The Polymarket conditional token contracts use specific smart-contract addresses on Polygon. Tax tools usually auto-detect them and label entries as "Polymarket — Buy" / "Polymarket — Sell" / "Polymarket — Redeem." Manually review a sample to confirm tagging is correct.
4. Convert USDC values to USD. Most tax tools treat USDC as ~$1.00 throughout; if you are constructing records by hand, use the daily USD price of USDC (typically 0.998–1.002) from a data source like CoinGecko for each transaction.
5. Calculate per-contract gain/loss. Proceeds (USDC received on resolution × USD rate) minus cost basis (USDC paid on entry × USD rate, plus allocated gas fees). Do this per position; the tax tool aggregates automatically.
6. Generate IRS Form 8949. The tax tool outputs Form 8949 lines (short-term and long-term, usually all short-term for Polymarket) ready to attach to Schedule D.
7. Report on Schedule D. Totals from Form 8949 flow to Schedule D. Net capital gain/loss flows to Form 1040, line 7.
8. File FBAR / Form 8938 if applicable. Evaluate whether your aggregate foreign-account balances triggered the thresholds above. File by April 15 (with an automatic FBAR extension to October 15 if needed).
9. Keep records for at least six years. Retain wallet export CSVs, tax-tool reports, and any USDC rate sources used. The IRS statute of limitations is generally three years, but six years for substantial underreporting and unlimited for fraud.

Recommended crypto tax tools for the international app

• Koinly — states that it syncs Polygon wallets.
• CoinTracker — states that it syncs Polygon wallets; Polymarket contract auto-tagging; integrates directly into TurboTax.
• ZenLedger — IRS-friendly output.
• TokenTax — higher-touch option for filers with complex Polygon + multi-chain activity.

Loss treatment and wash sale considerations

Polymarket net losses follow standard capital-loss rules under IRC §1211 and Publication 550:

• Net capital losses first offset net capital gains from any source (other Polymarket positions, equities, other crypto).
• Up to $3,000 of remaining net capital loss per year ($1,500 married filing separately) offsets ordinary income on Form 1040, line 7.
• Unused losses carry forward indefinitely until used.

There is no §1256 mark-to-market election or loss carryback available to Polymarket USDC-settled activity — those are §1256 regulated futures features that Polymarket contracts do not qualify for.

Wash sale rule and crypto

The §1091 wash sale rule applies to "stock or securities." The IRS has not formally extended wash sale rules to crypto or crypto-derivative contracts, although Congress has repeatedly considered legislation to do so. As of April 2026, most practitioners conclude the wash sale rule does not disallow crypto-to-crypto losses. Future legislation could change this — monitor annually before filing.

Polymarket US vs Kalshi: tax records compared

The gap is not a 1099: Kalshi does not issue a 1099 for event-contract profits, and whether Polymarket US does is not confirmed, so on both you build your return from the venue's own statements. Both hold your account in US dollars, and both are CFTC designated contract markets, so the Section 1256 question is the same on each. The international app is the outlier: USDC on Polygon, wallet reconstruction, and possible FBAR / Form 8938 questions — and US residents can only close positions there.

Polymarket links on this page open its international app. US residents can close existing positions there but cannot open new ones.

Affiliate links — we may earn a commission at no cost to you. Platform availability and tax treatment depend on your state of residence.