Jefferies & Co., Inc., expanded its New York City headquarters by leasing another floor in Tishman Speyer's 520 Madison Ave. The additional 16,745 square feet on the 5th floor brings the total square footage occupied by the financial firm to 116,545 square feet over 5 floors. At the same time, Jefferies also renewed its 29,107-square-foot lease on the 8th floor with the landlord. Dale Schlather of Cushman & Wakefield represented Jefferies in this transaction while Calvin Farley is the in-house agent for the landlord, Tishman Speyer Properties. The building is 97% leased.