Gary Carruthers has already persuaded over 24 former clients to transfer their business to Wells Fargo, according to a lawsuit.
JPMorgan argues that Wells Fargo gave him over $1 million in incentives to breach restrictions and switch jobs.
The bank says Carruthers, who spent 15 years at JPMorgan, had about 369 clients with roughly $250 million under management at the time of his resignation.