Bingham McCutchen LLP, one of nation's largest and fastest growing law firms, signed a 15-year lease for an additional three and a half floors at 399 Park Ave. The deal represents the largest law firm lease in Manhattan in 2002. The firm leased another 57,285 square feet in the building, including part of the 19th floor, and the entire 23rd, 24th and 26th floors. Bingham McCutchen also renewed 84,715 square feet on part of the 19th floor, and the entire 20th and 21st floors. The firm is consolidating its operations from 885 Third Ave. Cushman & Wakefield president of U.S. operations Bruce Mosler, chairman John Cushman and executive director Mitchell Barnett represented Bingham McCutchen. The landlord, Citigroup, represented itself.