A Bridgeport man pleaded not guilty yesterday in state Superior Court to stealing more than $20,000 worth of Confederate and late-1800s era U.S. stamps from a Norwalk company.

Keith Johnson, 30, of 1948 Seaview Ave., is charged with first-degree larceny.

Johnson was arrested in August after an investigation that began in May. Executives from MBI Inc., founded as The Danbury Mint, told Norwalk police a shipment of collectible stamps had been stolen, according to the arrest warrant affidavit.