Quantum SPAC Sues TradeStation, Monex Group Over Busted Merger

Quantum Fintech Acquisition Corp. sued Monex Group Inc. for at least $50 million, claiming the Japanese financial firm deliberately undermined its planned blank-check merger with Monex subsidiary TradeStation Group Inc.

The lawsuit accuses Monex of sabotaging the combination between its TradeStation unit, which operates a stock-trading platform, and Quantum—a special purpose acquisition company formed to find a merger—because its view of such blank-check deals soured after signing.

The case is the latest in a wave of litigation prompted by SPAC mergers, called de-SPACs, which combine a publicly traded entity with a private business that can then bypass an initial public ...