Susan M. Estes (born 1959) is an American business executive and CEO of OpenDoor Securities, a firm that primarily traded in United States Treasury securities.[1] Along with Brian Meehan, she co-founded the company in 2013, becoming the first woman to own and operate a bond trading business, an historically male-dominated industry.[2][3][4] The company provided anonymous electronic Treasury trading.[5] OpenDoors Securities ceased operations on January 13, 2021.[6]