Truist Financial Corp. is selling its stake in Truist Insurance Holdings, a subsidiary of Truist and the fifth largest insurance brokerage in the U.S., for $15.5 billion, the Charlotte-based bank said Tuesday. Truist Insurance Holdings’ sale is expected to provide $10.1 billion in cash for reinvestment, according to the bank. The sale — expected to close in the second quarter of this year — is to an investor group led by private equity firms Stone Point Capital and Clayton, Dubilier & Rice. Mubadala Investment Co. and other co-investors are also part of the investment. The agreement comes five…