Kalshi and Polymarket taxes: what the venues send, and what they don't
Facts about reporting, not tax advice. The IRS has not issued formal guidance on event contracts; talk to a CPA who knows trader taxation.
What forms you get
| Venue | Forms reported by tax practitioners |
|---|---|
| Kalshi | 1099-INT for interest and 1099-MISC for rewards; no form for trading profit itself. |
| Polymarket | No tax forms; the on-chain record is the audit trail. |
What that means
The absence of a form does not remove the obligation to report. Practitioners describe exporting the full trade history, computing net proceeds minus cost, and reporting the result — with an open question about characterization (Section 1256 contracts, gambling income, or ordinary income), on which the profession has not settled. Pick one reasonable treatment, apply it consistently, and document it.