Polymarket US

What it is

Polymarket US is the American product of the Polymarket brand, and it is a different thing from the international platform in almost every respect that matters: different operating company, different regulator, different custody of your money, different fee schedule, and a completely different authority deciding how a market ends.

The operator is QCX LLC, a Delaware company trading as Polymarket US. The CFTC's own filing record shows it designated as a contract market on 9 July 2025, with the remark that QCX now operates under the assumed name Polymarket US. An Amended Order of Designation issued on 24 November 2025 vacated the clause in the original order that barred futures commission merchants from intermediating transactions or carrying customer accounts — which is what makes a brokered route to this exchange possible at all. Clearing runs through QC Clearing LLC, trading as Polymarket Clearing, registered as a derivatives clearing organisation on 16 December 2024 and permitted to clear fully collateralised positions in futures, options on futures and swaps.

Fully collateralised is the mechanism, not a slogan. A buyer pays the contract price and can lose no more than that. A seller receives the price as proceeds and posts the full $1.00 payout per contract as margin — not the maximum loss, and there is no collateral release from offsets or from the price moving in their favour. The clearing house holds that margin until settlement. Balances are US dollars in a dedicated customer account that the exchange's own FAQ says is held separately from its operating funds.

The front end you actually use is a third entity: the app terms are published by PM US Tech (a/k/a QC Tech LLC), which describes itself as an independent software vendor front end that routes orders to the exchange and is not itself a contract market, clearing house, broker or custodian.

Availability

US residents, no state carve-out in either document we could open. The app terms, effective 25 September 2025, require you to be at least 18 or the higher age your jurisdiction sets, and say access may require KYC, AML and sanctions screening plus ongoing eligibility review. The exchange rulebook, dated 14 September 2026, asks an individual participant to be at least 18 and to have attained the age of majority in their state or country of residence. Neither names an excluded US state.

Identity verification is mandatory and it comes before your money. Signup is with a Google or Apple account, then a username, then full name, date of birth and residential address. Most verifications are described as instant; where automatic checks fail, a government ID and a selfie check are requested and manual review is quoted at three to five business days. The documentation is explicit that KYC must be complete before you can deposit or trade.

Getting money out is the more restrictive half. Deposits are debit card, ACH bank transfer or wire. Withdrawals go back to the original funding source only — not to a new or third-party account — and are processed first-in-first-out against the deposits that funded them, so the first $100 you withdraw returns to whatever method put the first $100 in. Deposits must fully clear first: three to four business days for card and ACH, one for wire, and you can trade with funds in flight but not withdraw them. Referral and promotional credit is a trading credit rather than cash — and here the venue's own two pages disagree. The promo-credit FAQ says the credit can never be withdrawn, even after the position it funded settles, and that only the resulting proceeds may become withdrawable once a real deposit has cleared; the refer-a-friend FAQ says credits "may be withdrawn upon position settlement or liquidation". Assume the stricter one.

Nothing we read claims availability outside the United States. The terms say the company makes no representation that the app is appropriate or available in any specific location, prohibit use from sanctioned or embargoed jurisdictions, and the funding rails are US debit cards, ACH and domestic wires. The mirror image is the international platform, which blocks the United States outright — one of the two is available to you, and it is decided by where you are.

Pricing

No subscription. A single symmetric formula, exchange-wide, effective from midnight ET on Thursday 17 September 2026: fee equals a coefficient times the number of contracts times price times one-minus-price. The charge therefore peaks at the 50-cent midpoint and falls towards nothing at the extremes.

That is the whole schedule — no per-category table, and the same rate on sports as on politics. The maker rebate is credited at the point of the fill rather than accrued, which is the difference from the international platform's daily rebate pool. At a penny or 99 cents the same 100 contracts cost a taker $0.07 and pay a maker $0.01. Everything is rounded to the cent with banker's rounding, and the exchange's own FAQ says a small fill can round to zero.

The 1.74% and −0.31% on this card are those midpoint figures expressed against the $1 payout, which is the only form in which they compare to another venue.

Taker rebates run off the previous calendar month's notional taker volume and are paid weekly: 10% back from $250,000, 25% from $1 million, 50% from $10 million. A participant may also be placed in a tier immediately by showing verifiable proof of their trailing-30-day volume on another prediction market.

No settlement fee is published, and withdrawals are documented as free. Referral credits are $25 to each side once the referred account deposits at least $10, capped at 14 referrals — but see Availability for what a credit is and is not.

Markets & resolution

This is the field that separates the two Polymarkets, and it is worth reading before the fee table. Internationally, Polymarket resolves nothing: the UMA optimistic oracle does, and a twice-disputed market ends at a token-holder vote. Here, the exchange decides, and its decision is the end of the matter.

The rulebook defines Source Agency to mean the Exchange, which in determining a contract's outcome references external sources designated in that contract's terms. Those sources may be organised as primary, secondary and tertiary, and the exchange may designate additional or substitute sources. The documentation groups them as government publications, the governing league or competition organiser, and named news outlets — sometimes a single outlet, sometimes several that have to agree — and states that unlisted sources have no effect on resolution.

What that looks like in a live contract: temperature markets settle on the National Weather Service Daily Climate Report for one named station per city — Central Park for New York, the airports for San Francisco, Miami, Chicago and Los Angeles — at 8:00 AM ET on the following day, delayed to 11:00 AM ET for review if the report disagrees with the 24-hour METAR observation, and settled at last fair market prices if nothing is published within a week.

Rule 10.4 is the part to read twice. Before settlement, the chief executive, chief compliance officer, chief operating officer, head of markets or their designate may at sole discretion review any circumstance affecting the reliability of the underlying event, may then determine the final outcome, and may reverse an outcome in the case of obvious error. The rule closes by stating that the company has full discretion in reviewing markets and that its determinations are final. Rule 10.5, covering contracts about a named person who dies or is incapacitated, settles them at last traded prices and says those determinations are final and not subject to review.

What is actually listed has outgrown the documentation. The getting-started page still says sports only, with politics, culture, finance and economics "coming soon". On 19 September 2026 the public API returned 2,611 open sports events and 1,167 open politics events, plus culture, daily city-temperature markets, Fed and jobs macro, technology, IPO and crypto price contracts. Read the API or the app, not the welcome page.

Combos settle by a committee, not by a formula alone. Two to ten markets become one position that settles once: every leg has to come in, one losing leg pays zero, and a leg that cannot resolve at all — a walkover, a scratched player, an abandoned fixture — is priced at its last fair market price by the Settlement Committee, whose decisions are also final. An unresolvable leg reduces the payout and never rescues a combo that already has a loser in it.

Integrations

The public gateway needs no key. Markets, events, series, sports schedules, search, order books, best bid and offer, settlement prices and price history are all open. The authenticated API handles orders, portfolio and balances, with two WebSocket streams — one private for orders, positions and balances, one for the book and trades.

Getting a key is gated on the phone, though. The SDK documentation states that you must download the iOS app, create an account and complete identity verification before you can generate keys in the developer portal, and that the private key is shown once.

Official SDKs are published for Python 3.10+ and TypeScript on Node 18+, both named polymarket-us. For anything institutional there is a separate stack: REST and gRPC, a FIX interface over AWS PrivateLink, a preprod environment, a drop-copy post-trade feed, and CSV downloads of trade, execution, position and fee reports plus streaming position and balance ledgers. The position and balance ledger exports carry a historical floor of 1 May 2026 — the documentation says pre-floor data is not retrievable — and those downloads are rate-limited to about five per minute per firm.

No MCP server appears anywhere in the documentation index.

Plan around the maintenance window: every Thursday from 02:00 to 04:00 ET, all open orders are cancelled, the API answers 503, and the books reopen empty.

Limitations

• Resolution is the exchange's own and there is no appeal. Rule 10.4 gives named officers sole discretion to determine an outcome and states the determination is final; Rule 10.5 makes its own determinations "final and not subject to review". If you think a market resolved wrongly, there is no oracle, no vote and no counterparty to argue with.
• Contract terms can change after you hold the position. Rule 10.3 lets the company modify contract specifications, including the settlement date and the payout condition, at any time, and the rulebook's definition of a Modification explicitly includes the interpretation of resolution criteria and the designation of alternative source agencies.
• There is no developer path that avoids the app. No iOS device, no API key, however much market data the public gateway will hand you anonymously.
• The published SDK packages are eight months behind their repositories. polymarket-us on PyPI is 0.1.2, uploaded 22 January 2026, and on npm it is 0.1.1, published 21 January 2026, while both GitHub repositories carry commits from 17 September 2026. Install from the registry and you are not running what the repository says it ships.
• The ledger exports begin on 1 May 2026. Position and cash history before that date is documented as not retrievable, so a reconciliation across the exchange's first months has to come from somewhere else.
• Whole contracts only on the retail app, although the rulebook permits fractional units. A dollar amount buys as many whole contracts as it covers and the remainder bounces back to cash.
• Money leaves the way it came in. Withdrawals return only to the original funding source, in deposit order, after a three-to-four-day clearing wait on cards and ACH; promotional credit never leaves at all.
• Resting orders do not survive the week. The Thursday maintenance window cancels every open order on the exchange.
• The venue's own onboarding documentation is out of date about what it lists, which is a poor sign for the rest of it.
• We could not verify what the exchange cost to buy. The CFTC record confirms that QCX LLC and QC Clearing LLC now operate under the Polymarket name; the widely repeated $112 million price traces to a founder's social-media post and to no filing we could open, so this card does not state it.
• Nobody here has funded an account. Everything above is read from the CFTC's filing record and orders, the exchange rulebook and risk disclosure, the app terms, the product documentation and the public API, on 19 September 2026.

Alternatives

Kalshi is the direct comparison and the reason to read the fee formula closely: the same shape, a 0.07 coefficient against this exchange's 0.0695, and a maker side that is charged on some markets rather than paid. ForecastEx is the opposite temperament — no sports, no direct accounts, and interest paid on collateral while a position is held. Robinhood Prediction Markets is the brokered route into this category generally, and the intermediation clause vacated in November 2025 is precisely what makes that shape of access possible on this exchange too. The international Polymarket is the one option here that is not open to a US resident at all.