Polymarket US vs sportsbooks in California
Why Polymarket US is legal in California when sportsbooks are not
With sports betting still illegal in California after the failed 2022 ballot measures, Polymarket US is one of the only legal ways for Californians to take a position on game outcomes. The venue is a CFTC-regulated exchange (the QCX entity launched in December 2025), so it operates under federal derivatives law rather than the state gambling statutes that keep DraftKings and FanDuel geofenced out. Its catalog is sports-led, which makes it the closest legal analogue to a sportsbook California currently has.
Current status and notes: prediction markets in California.
What the fees look like
Polymarket US charges a price-dependent taker fee in the same family as Kalshi's — a fraction of a cent per dollar at typical prices — with no hidden margin baked into the price itself. Sportsbook odds carry their cost inside the line (about 4.5% on a standard -110 spread); exchange pricing puts the fee on the ticket where you can see it.
| Venue | Fee per contract | Total taker fee |
|---|---|---|
| Kalshi | 1.75¢ | $1.75 |
| Polymarket US | 1.50¢ | $1.50 |
Exchange-side taker fees per each venue's published formula (rate × contracts × price × (1 − price), Kalshi rounds the order total up to the next cent). Fees peak at 50¢ and shrink toward the extremes. Most quoted cross-venue “arbs” are negative-EV after these fees — the taker-fee breakeven on a Kalshi/Polymarket pair is roughly 3.5–4¢.
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