Polymarket US is the version of Polymarket built for US traders. It runs on a CFTC-licensed exchange and clearinghouse that Polymarket bought in July 2025 (QCEX), and it is a separate venue from the crypto-based international platform that US users were geo-blocked from for years. For a US trader that means Polymarket now sits in the same regulatory category as Kalshi.
What we cannot give you is a definitive list of fees, markets or states. Those details are changing, and the sources we found disagree. So this article sticks to the structure, tells you what to check yourself, and explains what it means for arbitrage.
Why there are two Polymarkets
Polymarket settled with the CFTC in 2022 over offering unregistered swaps to US persons and spent the following years blocking US IP addresses. In July 2025 it acquired QCEX, an exchange and clearinghouse that already held CFTC licences, as the route back into the United States. The US product followed in late 2025. The international platform, a blockchain-based central limit order book that settles through UMA's optimistic oracle, continues to exist alongside it. The longer background is in What are event contracts? and Is prediction market arbitrage legal?
What changes for a US trader
- Regulation. The venue sits under CFTC oversight, like Kalshi, rather than operating offshore.
- Funding. Reporting indicates it is funded in US dollars rather than crypto. Confirm the current onboarding steps on Polymarket's own site.
- Rules and catalogue. Resolution rules, available markets and the fee schedule can differ from the international platform. Do not assume a market you saw on one exists, with the same rules, on the other.
What we are deliberately not claiming
Two details are worth checking at the source, because the secondary sources conflict or are out of date.
- State availability. Guides disagree on which states are excluded. Check Polymarket's current terms for your state before funding anything.
- Fees. Published breakdowns describe a fee that varies by market category, and the schedule has been changing. Read Polymarket's own fee page, then recompute your net edge with the real number. The international fees are covered in Polymarket fees explained.
What it means for arbitrage
Cross-market arbitrage works the same way: buy YES on one venue and NO on the other for the same event, and the payout is fixed once both legs fill. For a US trader, the pair is now two CFTC-regulated venues, which simplifies the legal picture. It does not change the risks. One leg can fill while the other does not, and the two listings can resolve differently.
The practical point is matching. Arbitrage Agent scans Polymarket and Kalshi markets. Before you act on a signal, confirm that the Polymarket market it points to is available on the venue you can use, with the same resolution rules. Edges stay thin, a median of roughly 0.7% per position after fees, held until resolution at a median of about 100 to 110 days. The live figures are on /proof.
Getting started
If you are a US trader and want the pair, open accounts on both venues, confirm your state is eligible on each, and use Arbitrage Agent to find the gaps. Today the Starter plan means signals and step-by-step guides with both legs ready to place; automated execution is still in final testing and rolls out to Operator subscribers first. If you are looking for another venue altogether, see Polymarket alternatives.
Related articles
- Polymarket Alternatives in 2026: What Exists and What Works for Arbitrage
- Is Prediction Market Arbitrage Legal? (2026 Guide)
- Kalshi vs Polymarket: Fees, Liquidity & Which Is Better for Arbitrage (2026)
- How to Arbitrage Polymarket vs Kalshi
Key terms: Event Contract · CLOB (Central Limit Order Book) · Cross-Market Arbitrage