Bankers Trust Co. President and CEO Suku Radia told employees Tuesday that the bank will operate under a single charter, based in Des Moines, effective next Jan. 1. Des Moines-based Bankers Trust is the parent of both banking operations, but each has held a separate charter. The merger is awaiting approval from banking regulators. Tim Kintner, executive vice president for consumer, private and regional banking markets, said in an email that there was no value to customers in having separate charters. “We are merging charters because the value to our customers and employees of having two Bankers Trust charters in Iowa no longer outweighs the costs and additional work of keeping them separate. These costs include increased financial services regulations that consume even more resources under a two-charter structure,” he said.