Underdog’s in-house prediction exchange UDX is off to a fast start, having topped the $1 million single-day volume mark only 10 days after launching.
The vast majority of Underdog prediction market volume still goes through third-party exchanges, as has been common when companies move from a broker role to running an exchange themselves, but the early growth combined with a recent parlay self-certification mean that Underdog may be moving more of its volume to its in-house exchange fairly quickly.
Underdog initially entered prediction markets offering contracts from Crypto.com and then Kalshi, but in March it announced that it would launch its own exchange, buying Aristotle Exchange’s designated contract market (DCM) from PredictIt. A DCM is the regulatory status of exchanges like Kalshi, Polymarket US, and Crypto.com.
UDX processed its first test trades on July 17. It then publicly announced its launch on July 18. Volume has grown in the days that followed.
Underdog doesn’t publish weekend trading data, and unlike CME, doesn’t group it in with Mondays. As a result, its trading volume on Saturday and Sunday is unknown.
On Monday, it topped the $1 million mark for the first time, hitting $1.2 million.
That growth means that after only 10 days, Underdog’s volume already exceeds the long-established ForecastEx, as well as DraftKings’ DKeX, which launched a month ago and topped $1 million for the first time Sunday.
The early performance puts Underdog alongside Robinhood for the strongest such performance of a new exchange. Exchanges that previously acted as brokers to third-party exchanges before launching an in-house option have an advantage in terms of early volume as they can simply direct existing customers to the new exchange, often without them noticing where their trade is actually executed.
While those are strong early numbers, they are still not even remotely near Kalshi’s daily volume. Volume on Kalshi on July 27 was $1.05 billion, or 850 times Underdog’s.
The faster early growth also comes despite a fairly short runway from announcing its DCM purchase to launch. Robinhood bought MiaxDX in November before launching at the end of May. DraftKings bought Railbird in October before launching in June.
However, as with other businesses that have acted as a broker, the vast majority of prediction market activity from Underdog still goes to those external exchanges. Underdog’s terms and conditions say it routes customers to Crypto.com and Kalshi as well as the in-house UDX. Robinhood and DraftKings also stepped up the share of volume that goes through their in-house exchanges in their opening weeks.
Last week, while announcing the launch of its in-house exchange, Underdog revealed that it had processed $6.49 billion worth of trades since launch, or $4.4 billion in 2026. That would be equal to around $23 million of volume per day.
Currently, all of UDX’s trading activity is on Major League Baseball, suggesting that only users buying these contracts are directed from Underdog to UDX. However, it may offer more markets soon. On Tuesday, Underdog self-certified to offer parlay contracts on UDX. The parlay self-certification was first reported by PredictionMarketPulse.
