The latest way to predict the market now is @PolymarketTrade's Combo That is to say, a string of sub orders. It is not a pure mathematical algorithm like the previous A+B=1, nor is it considered as order book matching But instead, an RFQ (Request for Quotation) mechanism was used. For example: You combine 2-10 markets into one leg: settle all in the direction you choose to win, and reverse any leg to zero the entire order. Under independent events, the fair price is approximately equal to the product of the prices of each leg. 0.60 × 0.55 × 0.70=0.231, with a winning payment of $1. But what you see is not this product. The system sends the combination to the market maker for bidding within about 400ms, and you have about 10 seconds to accept the best offer. Related legs (same game win/loss+handicap) are not simply multiplied, and market makers will adjust their prices. The quoted price is usually worse than the pure product, and the difference is their margin. The international station will be launched on June 10th, and the US station will be in beta on August 5th and open to app users around August 21st. The specific RFQ execution process can be seen from the official document as follows: 1. The user creates an unsigned request requesting the price of this Combo. 2. The RFQ system sends the request to the connected market maker and begins bidding. 3. Market makers submit signed Quotes (price, quantity, signed order) within a submission window of approximately 400 milliseconds. 4. The system returns the best quote to the user. 5. The user signs the transaction within the acceptance window of about 10 seconds, otherwise it will be invalidated. If the market maker enables Last Look, the system will ask it to confirm again. 7. The market maker confirms or rejects within approximately 1 second. 8. The system executes the accepted Combo. The user and the market maker have received execution updates. Other connected market makers have received broadcasts confirming transactions. The mechanism of the US site is slightly different: Polymarket.v1. RFQAPI (REST and gRPC) management. Market makers can create or replace their own quotes for an RFQ by quoting both the buy and sell prices. After the user accepts one side: RFQ has been turned off and publicly broadcasted as rfq_closed. The selected quote becomes accepted, and the market maker receives a private quote_accepted with a confirmation deadline. The market maker confirms the transaction before the deadline or rejects the Delete Quote. The last look window configuration in the document is about 3 seconds. After confirmation, the quotation will become confirmed, and then the paired order will be submitted according to the execution deadline (approximately 1 second waiting time). Why are the implementation methods of international stations and US stations different The international site is the on chain prediction market, while the US site is QCX's compliant exchange under CFTC supervision. Contracts, fees, invalidation rules, and RFQ interfaces are all handled separately for US regulated products, so the process is similar, but the parameters and interfaces are not completely the same. Official document original link: International Station Combo Process: https://docs. ((((polymarket.com))))/trading/combos/overview Chinese version: https://docs. ((((polymarket.com))))/cn/trading/combos/overview Definition of Combined Position: https://docs. ((((polymarket.com))))/trading/positions/combinatorial International Station RFQ (Market Maker): https://docs. ((((polymarket.com))))/market-makers/rfq/overview Combo description for the US station: https://docs.polymarket.us/trader-guide/combos American Combo FAQ (including compensation and LFMP): https://docs.polymarket.us/faqs/combos-faqs US RFQ API: https://docs.polymarket.us/institutional/rfqs/overview