Polymarket US is the business name of QCX LLC, a designated contract market under the Commodity Futures Trading Commission. It is a separate exchange from the on-chain market in the Polymarket review. The Polymarket and Kalshi comparison sets the two structures next to each other.
What the product is structurally
QCX LLC is a Delaware limited liability company headquartered in Boca Raton, Florida. The CFTC designation record lists it as designated on July 9, 2025, under the name Polymarket US.
The July 9, 2025 order describes an anonymous electronic central limit order book. It also states that listed contracts are cleared fully collateralized at a registered derivatives clearing organization. That order barred futures commission merchants from carrying customer accounts unless the order was amended. The designation file lists a later amended order, and that order vacates the bar.
These are event contracts of the kind described in prediction markets. The September 2026 fee notice prices a contract from $0.01 to $0.99.
How it works in practice
Participants trade with other participants on the central limit order book. The exchange matches orders. The July 9, 2025 order does not describe the exchange as taking the other side of a contract.
A match is priced in that $0.01 to $0.99 range. The fee notice uses the price inside a formula that rises when the price is near $0.50 and falls when the price is near either extreme. Resolution still depends on the contract’s own rules for the outcome.
Fees and pricing mechanics
The standard fee is the coefficient times the contract count times the price times one minus the price. A CFTC fee notice dated September 21, 2026 raised the taker coefficient from 0.06 to 0.0695, effective September 17, 2026 at 12:00 a.m. Eastern Time.
One hundred contracts at $0.50 produce a taker fee of $1.7375 under the 0.0695 coefficient, before any further rounding. The same inputs at the old 0.06 coefficient produce $1.50.
On October 15, 2026, every participant gets a maker rebate coefficient of minus 0.0125. An October 2, 2026 CFTC filing replaces that flat rebate on October 19. Prior-month maker volume below $10 million gets no rebate. Volume of at least $10 million, $50 million, and $200 million maps to minus 0.0035, minus 0.0070, and minus 0.0104. The filing leaves the taker coefficient at 0.0695. The maker fee stays zero.
Limits, eligibility, and availability
The July 9, 2025 order required fully collateralized clearing and, until amended, a non-intermediated model. The later amended order removes the futures-commission-merchant prohibition. The September 2026 fee notice does not list a minimum balance, a state-by-state map, or a residency test.
The international Polygon venue, covered in the Polymarket review, is the market that blocks new U.S. orders. Polymarket US is the designated exchange. The fee notice does not say the two books share liquidity.
Tradeoffs, risks, and limitations
The taker coefficient changed in September 2026, from 0.06 to 0.0695. The flat maker rebate ends October 19, 2026, when volume tiers replace it. Later filings can move either number again. A contract priced in cents can expire worthless when the outcome goes the other way. Designation requires surveillance and listing rules. It does not set the outcome.
Polymarket US and the Polygon venue do not share one order book. A price on one is a price on that book only.
