Regulation
- Kalshi — CFTC-regulated designated contract market (DCM). Federally licensed, operates in all 50 states for sports + non-sports.
- Polymarket — Operates offshore via Polymarket Limited (Cayman Islands). Currently restricted to non-US users following CFTC settlement, though VPN access is widespread.
- PredictIt — Operated by Victoria University of Wellington under a CFTC no-action letter. Limited markets per user; primarily political. Wound down in 2023 with phased reopening.
Sports coverage
- Kalshi — Full sports coverage: NBA, MLB, NHL, EPL, MLS, PGA Tour, championship futures, MVP, individual game outcomes.
- Polymarket — Heavy on political and macro markets; growing sports markets (NFL, NBA championships, individual game lines on majors).
- PredictIt — Almost entirely political; some niche markets but no live sports betting.
Liquidity
Polymarket has the deepest liquidity overall (~$200M+ monthly volume), but most of it is concentrated in headline political markets. Kalshi has tighter spreads on US sports markets specifically (typically 1–3¢ on majors). PredictIt has thin liquidity outside of US presidential betting.
Fees
- Kalshi — Charges trading fees (0.07% per side, capped at 7¢ per share) plus settlement fees. Effective cost on a winning bet is ~1–2%.
- Polymarket — No trading fees; small gas fees for on-chain settlement (Polygon network, usually <$0.50).
- PredictIt — 10% withdrawal fee + 5% profit fee. Highest fees of the three.
Bottom line for sports bettors
For US-based sports bettors, Kalshi is the practical choice — federally regulated, full sports coverage, deep liquidity. Polymarket has better political market depth but US access is technically restricted. PredictIt isn't competitive for sports.