US custodian State Street is suing three of its former executives for allegedly poaching the staff of an entire business unit and building a company to rival its status as the world’s largest securities lending agent.

Craig Starble, who led State Street's securities finance business until May last year, along with Peter Economou, who took over this role only to relinquish it two weeks ago, have also been sued by their former employer for allegedly breaching terms of their employment contracts and attempting to steal business.