Polymarket Files Combinatoric Athletic Outcome Contracts with CFTC as Parlays Drive Prediction Market Volume
Polymarket is preparing to launch parlays on its platform as it expands in the US. The multileg wagers have become increasingly popular at Kalshi, driving recent increases in trading volume.
The bets offer users the hope of large payouts. In reality they are a great money spinner for bookmakers. As much as 70% of all sportsbook profits come from parlays. Polymarket refrained from calling the contracts parlays in its filing with the Commodity Futures Trading Commission (CFTC). It instead referred to them as Combinatoric Athletic Outcome Contracts.
After eighteen years on bookmaker trading floors this move looks familiar. Operators have long known the margin power of correlated outcomes. Prediction markets are now learning the same lesson in public.
Parlays Driving Profits For Kalshi
Kalshi first self-certified parlays in September last year and has gradually expanded the markets it allows users to combine. They are increasingly becoming a key driver of trading volume on the platform.
Volume grew to $14.8 billion in April, up from $13 billion in March. About $1.2 billion of the $1.8 billion difference from March to April was parlays.
Kalshi users have lost more than $117 million on parlays this year from $800 million wagered. The platform has retained $35 million in fees. In October, shortly after introduction, parlays accounted for only 1.8% of total volume. Last month that rose to a high of 22%.
Market makers such as Susquehanna respond to Request For Quotes. In its API provided to these companies Kalshi supplies user identifying information. This lets the platform limit users in the same way sportsbooks restrict winning bettors.
The data says the model works. Parlays deliver both volume and retained revenue. Sportsbooks have run the same playbook for years.
Polymarket Volume In US Spiking As App Goes Live
Polymarket has been slow to relaunch in the US following CFTC approval last year. The platform was expected to be available nationwide in November last year but it continued to keep most users on a waiting list.
That is changing. Daily volume in sports markets from US residents increased to over $22 million this month, up from just a few million in March.
Kalshi remains dominant at around $134 million in daily sports trading. The launch of parlays may help Polymarket bridge that gap.
From the trading floor view the timing makes sense. US availability plus multileg products equals immediate volume upside. The question is execution and risk controls.
DraftKings Also Launches Parlays On Prediction Market Platform
DraftKings also launched parlays on its prediction market platform earlier this month. CFO Alan Ellingson said he is confident the company will attract users due to its pricing and trading expertise.
“There’s a long way for predictions to go. I’m optimistic. We think it’s going to be a fantastic growth story.”
Co-founder Paul Liberman said he expects further expansion of the range of markets on offer.
“I think that in sports, we’re gonna see faster, more dynamic micro markets appear that don’t exist yet. We’ve seen that already with RFQs and parlays. I think you’re gonna continue to see innovation there in terms of how dynamic the prediction markets are gonna be able to be on sports.”
DraftKings has also indicated that it would introduce microbets to prediction markets. The wagers have been criticized as encouraging problem gambling. The company is facing a lawsuit from the Public Health Advocacy Institute (PHAI).
The Risk Layer Operators Already Know
Parlays boost volume and margins. They also concentrate risk. Bookmakers learned this the hard way across thousands of correlated legs every weekend.
Kalshi has already moved to user-level controls via its market maker API. Susquehanna and others can decline RFQs from consistent winners. This mirrors sportsbook sharp limits but it sits awkwardly next to the not-a-betting-platform positioning.
Matt Kalish called out the tension directly. The same mechanisms that protect margins also undermine the pure exchange narrative. Prediction platforms are discovering they cannot escape the operational realities of asymmetric information and adverse selection.
The CFTC filing language matters here. Combinatoric Athletic Outcome Contracts sounds cleaner than parlays. Regulators and users will still treat them as multileg wagers with the same payout skew and house edge characteristics.
The Bottom Line
Prediction market platforms are adopting the parlay playbook that has powered 70% of traditional sportsbook profits. Kalshi proved the volume impact with $1.2 billion of April growth tied directly to parlays and $35 million in retained fees from $117 million in user losses. Polymarket is now following with its CFTC filing while its US sports volume climbs above $22 million daily. DraftKings is active on the same front with both parlays and planned microbets.
The data is on the table. Multileg products deliver revenue. They also require sharp risk controls, user segmentation, and clear regulatory positioning. Operators who have run these books for years watch the prediction space converge on the same mechanics. World Cup 2026 will test who priced the correlations best. The platforms that combine volume growth with disciplined liability management will keep the edge.
