How prediction-market parlays work, and why market makers carry the risk
On prediction markets, a parlay is priced by market makers answering a request for quote, not by a sportsbook. Market makers took on about $18 billion of parlay risk in a single week in October 2026, a market maker told the NEXTPredict NYC conference.
What happened
A parlay at a sportsbook has one price, set by the book, which also carries the risk. On prediction markets, the equivalent product is priced through request for quote (RFQ): the customer asks for a price on a combination, the exchange sends the request to market makers, and they compete to take the other side. At ProphetX, founder Dean Sisun said, 30 to 40 high-frequency market makers are “plugged in to respond to orders in half a second to a second,” he told a panel at the NEXTPredict NYC conference in October 2026.
The volume is growing fast. Bernard Marantelli, founder of market maker White Swan Data, said market makers took on $18 billion of parlay risk across prediction markets in the seven days from October 20, and he expects about $30 billion by Christmas. “Growth is out of control… in a good way,” he said, comparing the firms that will dominate the business to trading houses such as Susquehanna.
The details
Big firms are not the only winners. Jacob Meleka, a technical engineer at Polymarket, said teams of one or two people have found edges in niche parlays, especially political ones, and that Polymarket is looking into weather and other non-sports RFQ contracts. Marantelli gave the example of a contact who hedges snow risk for Chicago’s airport.
What it means
For the customer, the price of a combo depends on how many makers compete for it and on the exchange’s fees. To see what a parlay’s price implies, multiply the decimal odds of the legs in our accumulator calculator and compare the result with the quote, and read how betting odds work. The legality of sports event contracts is still being fought in court; see the CFTC’s lawsuit against Utah.
Key facts
| Pricing method | Request for quote (RFQ): market makers compete to take each combo |
|---|---|
| Platforms named | Polymarket, ProphetX |
| Parlay risk | About $18 billion in the seven days from October 20, 2026 |
| Forecast | About $30 billion a week by Christmas (Bernard Marantelli, White Swan Data) |
| Response time | Half a second to a second (ProphetX) |
| Market | United States · regulator: state gaming regulators |
| Published | October 28, 2026 |
Questions and answers
How are parlays priced on prediction markets?
Through request for quote: the customer asks for a price on a combination, the exchange sends the request to market makers, and the makers compete to take the other side, often within a second.
Is a prediction-market combo the same as a sportsbook parlay?
The bet looks similar, but the price comes from competing market makers rather than the sportsbook, and the market maker, not the exchange, takes the other side. Fees and settlement rules also differ.
How big is prediction-market parlay trading?
Market makers took on about $18 billion of parlay risk in the seven days from October 20, 2026, according to Bernard Marantelli of White Swan Data, who expects about $30 billion by Christmas.
Related stories
Sources
This story is our own summary and analysis of the reporting above; figures are as reported on the date shown. Spotted an error? Email contact@sportsbooks.ro.
The Sportsbooks editorial team reviews licensed sportsbooks from public, sourced evidence: regulator registers and enforcement notices, App Store ratings and each operator’s published terms. Every review is re-checked at least every 90 days.
Editorial policy · How we rate