I does not seem like IG is moving into US for the FX side. I bet they are getting ready to ride the Crypto 2.0 wave as the Institutional side gets ready to takeover this new casino.
News - https://www.financemagnates.com/forex/brokers/ig-group-gets-us-regulatory-approval/
News - https://www.financemagnates.com/forex/brokers/ig-group-gets-us-regulatory-approval/