A memo reported in the press confirmed the executive's departure after two decades of service earlier today, although it did not reveal whether he will be joining another company.
The Wall Street Journal indicated that Mr King is expected to be taken on by Barclays; however, sources close to the situation have been quoted by news providers as saying such a move is not yet certain.
According to the publication, Mr King's role would likely involve trying to strengthen Barclays' European investment banking business.
Barclays has already recruited several former Citi personnel this year. In July, Reuters reported that it had appointed mergers and acquisitions (M&A) banker Mark Todd to its European M&A division.
He joined Matthew Ponsonby, Julian Vickers and Jim Peterkin, who also made the move between the two banks.
Written by Asim Shah