The 4,172-square-foot house was built in 1901.
Posner is managing director of Morgan Stanley and heads the mortgage finance and specialty finance equity research team.
He formerly worked in the investment banking group of Morgan Stanley and formerly served as infantry captain in the U.S. Army. He also is the author of Stalking the Black Swan.
He received his degree from Yale University and M.B.A. from the University of Chicago Graduate School of Business.
Eby is an orthotics, foot specialist and orthopedic physical therapist at Bradley & Monson, a physical therapy clinic in New York.
She received a degree in biological sciences from Northwestern University and master's degree in physical therapy from Columbia University.
Intrater is a partner and senior member of finance and risk practice at Oliver, Wyman & Co., an international management consulting firm in New York.
He is a graduate of Harvard University.
Ostroff has been the assistant vice president in the advanced development division of Citibank in New York.
She received her degree from George Washington University and her M.B.A. from New York University.
According to BlockShopper.com, there have been 566 home in Upper West Side during the past 12 months, with a median sales price of $820,000.
Address: 157 West 91st Street
Buyer(s): Posner, Kenneth A, Eby and Susan C
Seller(s): Intrater, Marc Jeffrey, Intrater and Pamela Ostroff
Sale date: Apr. 26, 2010