The entrance of prediction market operator Kalshi into the same-game parlay space has sent an earthquake through the American betting industry with shares in dominant players DraftKings and Flutter plunging over 11 per cent, wiping $8 billion off their combined value.
In an extraordinary market reaction to Kalshi’s growing presence in the NFL betting space, shares in DraftKings dropped to US$37.60, down 11.6 per cent, while Fanduel owner Flutter’s share price fell to US$254.00, a 10.3 per cent drop.
The dramatic change in investor sentiment also impacted Entain, which saw a 3 per cent share price fall due to its American involvement in the BetMGM joint venture.
Entain is the parent company of the Ladbrokes and Neds brands in Australia, while Flutter owns Australian market leader Sportsbet.
So what caused the sudden share price drop?
Kalshi, the prediction market platform, which is legally not a bookmaker but a financial assets trading platform, launched a “build your own parlay” product on Monday ahead of two key National Football League matches.
This is crazy! The new combo experience on @Kalshi lets you build your own market for the NFL games tonight. pic.twitter.com/7LLuIDwvLp
— Noah 💥 (@Nostroah) September 30, 2025
The platform, which operates more like an exchange than a traditional sportsbook, utilises market makers or professional traders to provide a "request for quotation" for other users.
Users accept the terms of that contract, which may include aspects such as the game result, first touchdown, total points or overall winner, or a combination of the above.
Kalshi has been grabbing considerable market share from the other sportsbooks, but the entry into the lucrative same-game parlay space could be a game changer.
According to Yahoo Sports, the Kalshi same-game parlay products held only $255,757 across 1229 trades, generating just over $1750 in fees for the platform.
But that move has struck fear into investors in the sportsbooks in the same-game-parlay-obsessed American market where around half of revenue and a quarter of turnover are generated from that source.
Kalshi has greater reach than the traditional sportsbooks as it is federally regulated by the Commodity Futures Trading Commission, meaning it doesn’t require state-by-state licensing.
It can target states like California and Texas where sports betting is yet to be legalised.
Waterhouse VC
While its first foray into the same-game-parlay market wasn’t an overnight success, its growing profile and presence is disconcerting for a sports betting industry that has grown unchallenged over the past seven years. Monday’s soft launch wasn’t marketed.
Kalshi has an agreement to offer its services through the popular Robinhood trading platform, which it recently confirmed was generating about half of its turnover. The same-game product is not yet available through Robinhood.
Same-game parlays evolved from the same-game-multi product, which was developed and popularised in Australia.
