IG Group, a British online brokerage, agreed on Thursday, July 30, to acquire Underdog, a U.S. fantasy-sports and prediction market operator, for as much as $1.3 billion, placing its biggest bet yet on the booming market for trading real-world events.
Underdog, which began offering them in September 2025, gives IG an established U.S. consumer brand with about 952,500 monthly active users during the first half of 2026.
- The deal values Underdog's business at about $1.1 billion, with shareholders eligible for a further $200 million if it meets performance targets, according to IG's regulatory filing.
- IG will pay approximately $380 million in cash, issue about $583 million of shares and refinance roughly $160 million of Underdog debt.
Underdog recorded $466 million in revenue during the year through June, up 21%, while its accumulated customer base included 5.5 million people who had deposited money.
A shortcut into prediction markets
Underdog started as a consumer app offering daily fantasy sports, but later added predictions by routing customer orders to exchanges operated by Crypto.com and Kalshi.
Underdog says customers have generated nearly $6.5 billion of prediction market volume since September, and that puts it just above Polymarket U.S. at a reported $6.48 billion, but far behind Robinhood's $32.5 billion and Kalshi's $86.5 billion over the comparable period.
But those figures measure orders placed through Underdog, rather than activity on its own exchange. The acquisition is expected to close in late 2026 or early 2027, subject to U.S. regulatory approval.