The Park Avenue pad occupies both the 30th and 31st floors of the co-op building on 733 Park Avenue. It comes with three landscaped terraces, floor-to-ceiling windows in the foyer, and a private elevator.
Allen was once one of the wealthiest men on Wall Street. His son, Herbert Allen Junior, now runs the boutique investment bank Allen & Co. and hosts the company's annual tech/media/finance conferences in Sun Valley each year.
Allen Sr. originally bought the UES penthouse for $526,500 in the '70s when the building was still new, according to The Daily News. The penthouse was listed with Fox Residential Group, and the buyer will remain unknown until the sale is registered next week.