Underdog CEO Jeremy Levine said Thursday his company is being sued in the Delaware Court of Chancery by Aristotle International Inc. and subsidiary Aristotle Exchange Holding Company, the creators of the prediction market exchange and clearinghouse Underdog acquired earlier this year.

Underdog acquired Aristotle’s exchange and clearinghouse in March. A source with knowledge of the claims said Aristotle is now suing in the wake of Underdog’s purchase by IG Group for $1.3 billion last month. Aristotle received Underdog equity as part of the deal involving the exchange and clearinghouse, the source with knowledge of Underdog’s perspective said, and wants a better return than it’s getting from IG Group’s takeover.

The Delaware Court of Chancery has not yet published the full case file.

“First time being sued,” Levine wrote in a statement on X. “With a bunch of claims like ‘fraud,’ ‘scheme,’ ‘conspiracy,’ etc. Apparently the Aristotle folks are unhappy with the money they’re making from the sale of their licenses, even though they will end up making more than anyone else in our sale to IG.”

Aristotle declined comment but confirmed the lawsuit had been filed.