Prediction markets have caught onto a strategy sportsbooks mastered long ago: multi-leg bets, or parlays, are driving retail interest to new heights. Since Polymarket launched its Combos feature in June 2026, allowing users to combine several prediction outcomes into one bet, the popularity of these wagers has exploded. Kalshi quickly followed suit, hitting over $100 million in volume within just a week of opening its combo bets to users.
How combo bets stack the odds
Combo bets multiply the probabilities of each individual leg, making the overall chance of winning much slimmer but offering a bigger payout. For example, three bets each with a 50% win probability combine to just a 12.5% chance of success. Polymarket prices these combos via a request-for-quote system, meaning market makers set prices individually for each bet bundle rather than using an open order book. Institutional traders and sharp market makers sit on one side, quoting prices to retail bettors on the other, creating a distinctive market dynamic.
Retail losses mount as house edge compounds
Data from mid-2025 to March 2026 shows median retail returns in prediction markets at negative 8%, worse than the roughly negative 5% recorded by traditional sportsbooks in the same period. Multi-leg bets only deepen losses. Every additional leg adds a margin to the price, and since the probabilities multiply, small edges quickly snowball into significant expected losses. A three-leg combo doesn’t just add one margin layer, it stacks them, turning retail bettors into consistent losers.
During the 2026 World Cup, these platforms saw unprecedented engagement, attracting new demographics such as more female participants, a group previously underrepresented in prediction markets. Integrations with services like Robinhood helped amplify reach and volume during the tournament’s peak excitement.
This content is for informational purposes only and does not constitute financial advice.
