Top executives at Guggenheim Partners carried out a series of deals with companies close to the Wall Street firm’s leadership that have triggered concerns over possible favouritism and self-dealing from its own internal compliance, auditing and investment teams, a Financial Times investigation has found.

The deals saw the $240bn Wall Street asset manager invest at least $1bn of client money in companies where Guggenheim’s top officers and biggest shareholders had personal ties, transactions that were in some cases red flagged by the firm’s own compliance department for a lack of due diligence.

The investments have prompted inquiries by the US Securities and Exchange Commission, which received a whistleblower complaint in February 2016 alleging Guggenheim’s business culture encouraged senior executives to put themselves ahead of clients and prompted compliance to look the other way or face retaliation, according to people briefed about the complaint’s contents.