How to Give Your CPA Your Prediction Market Trades: A Checklist

Many accountants haven't worked with prediction markets before. The more organized your records are, the faster they can do your return, and the less you pay for their time. Bring them everything on this list.

1. Where you traded

• Every platform you used during the year: Kalshi, Polymarket, and any others.
• For Polymarket, the address of every wallet you traded from. See combining multiple wallets.

2. Any tax documents you received

• Kalshi's year-end tax statement, downloaded from your Kalshi account.
• Any other 1099 forms related to your trading accounts.

3. Your results, position by position

• Every closed position for the year, with open date, close date, quantity, gross P&L, fees and net P&L.
• A total of fees paid, so your preparer can confirm they're counted once. See why fees matter.

4. Positions open at year end

• Every Kalshi position you held on the last business day of the year, with its market price that day. These are taxed under mark-to-market.
• Open Polymarket positions too, so your preparer knows what's still pending.

5. The treatment you chose for Polymarket

Tell your preparer whether you're using 60/40 or holding-period treatment for Polymarket, and why. Ideally, decide this together before they start.

6. Carryovers from last year

• Any capital loss carryforward from last year's return (Schedule D).
• Your net Section 1256 results for the last three years, in case a loss carryback makes sense.

7. The draft forms

If you can hand over draft versions of Form 6781, Form 8949 and Schedule D, your preparer's job becomes checking and entering numbers instead of building them from scratch.

This guide is general information, not tax advice. Tax treatment of event contracts is still evolving, so confirm how it applies to you with a tax professional.