Kalshi vs Polymarket taxes for US traders

What Kalshi says it issues

Kalshi's help article "What Tax Documentation Does Kalshi Provide?" (dated June 22, 2026) lists four forms for users who hit IRS reporting thresholds: 1099-INT for interest payments from Kalshi, 1099-MISC for credits and rewards, 1099-B for "transaction proceeds from broker transactions (crypto transfers)", and 1099-DA for digital asset transaction reporting from ZeroHash.

A separate Kalshi article on Social Security Numbers gives two thresholds: more than $10 in interest in a year, and more than $600 in incentive credits such as referral bonuses in a calendar year.

Forms arrive by email from Zenwork, Kalshi's tax form provider, and also sit in the Account tab under Tax Info. Kalshi says that if no 1099 appears, "it is likely because you did not meet the IRS thresholds required for issuance."

• 1099-INT: interest on cash balances, threshold above $10.
• 1099-MISC: credits and rewards, threshold above $600.
• 1099-B: crypto transfer proceeds, per Kalshi's wording.
• 1099-DA: digital asset reporting from ZeroHash.

Kalshi's profit and loss statement

None of the four forms above is described as covering event-contract trading gains. What Kalshi provides for that is a Profit and Loss statement, downloadable per year from Account, then Tax Info.

Kalshi says it uses the First-In-First-Out method to compute profits and losses, that the figure includes fees and any rebates, and that the data is updated on the first morning of each month, so a mid-month download can miss recent trades.

Kalshi's own caveat: the statement "is intended as a tool to assist members", is not tax advice, and "each member should consult with a tax professional for any questions and is responsible for ensuring the accuracy of all returns."

What Polymarket's help center covers

Polymarket's help center collections are Getting Started, Markets, Trading, FAQs and Troubleshooting. A search of help.polymarket.com and its home page turned up no article on taxes, 1099s or tax documents as of September 8, 2026.

What the docs do say is mechanical. Trades settle in USDC, taker fees are charged in USDC and rounded to 5 decimal places, USDC deposits and withdrawals carry no Polymarket fee, and markets resolve through the UMA Optimistic Oracle, so every trade, redemption and transfer is an on-chain record tied to your wallet address.

That record is what you have. Polymarket does not publish a statement equivalent to Kalshi's FIFO P&L, so the wallet history is the starting point for any reconstruction, whether you or a tool does it.

How event contracts are treated

Neither venue's pages state how a US trader should characterize event-contract gains. Kalshi limits itself to FIFO accounting for its statement and a pointer to a professional. Polymarket says nothing.

TraderTax's calculator, built for this question, models three treatments side by side: short-term capital gain on Form 8949, which it calls "the common default"; Section 1256 60/40 on Form 6781, which it calls "generally considered aggressive"; and gambling under section 165(d). Its disclaimer says the IRS and Treasury "have issued no formal tax guidance on prediction-market event contracts as of July 2026" and that its output is "a range, not advice."

Read that as the state of play, not a recommendation. Which treatment applies to you is a question for a professional who has seen your trades.

What a tax tool needs from you

For Polymarket, a wallet address. Awaken lists Polymarket among its supported integrations and takes data "via API, CSV, or wallet address"; for US filers it produces Form 8949 and Schedule D. The preview is free and report downloads are paid: $99 per year up to 300 transactions, $199 for 1,000 to 5,000, $599 for 10,000 to 50,000.

For Kalshi, the yearly P&L statement and, if issued, the 1099s from Zenwork. TraderTax's calculator asks for platform, market type, net profit or loss, optional gross winnings and losses, trade count, other trading income, bracket and state, and returns the three-treatment comparison.

For a hand-kept ledger across both venues, Manage Bankroll is manual entry only: free for 5 platforms and 50 transactions, $100 per year for unlimited history. It describes no tax export, so it is a record, not a filing.

• Polymarket: wallet address (Awaken), or a CSV you export yourself.
• Kalshi: yearly P&L statement from Account, then Tax Info, plus any Zenwork 1099s.
• Both: your own note of which treatment your professional chose, since the tools model several.