Biddle served in Army counterintelligence in Germany and on the Army ski team. He returned to earn an MBA at USC, then went into finance as a member of the American Stock Exchange and was on the Board of Governors from 1990 to 1995. He founded a software firm, BlueNote Analytics (options valuation).
In retirement Biddle was president of the Dune Alpin community in East Hampton, N.Y., and when in New York he joined occasional lunches of 1952 at the Princeton Club.
Biddle died Sept. 20, 2020. He is survived by his wife, Gail; and son James. The class offers its sympathies to them.