"The building provides us with an excellent location, top tenant amenities and a dynmaic environment in the heart of the Financial District," says Jole Carpenter, co-manging partner of Sullivan & Worcester, in a statment.

The firm has been at the property since 1982, which boasts 830,000 square feet in total and floor plates ranging from 12,000 to 25,000 square feet, as well as 2,000 square feet of retail attached to its three-story lobby. The trophy is attached to the Langham Hotel and averages a high-rate of occupancy, according to CB Richard Ellis. Putnam Investments, Acadian Asset Management, Jones Lang LaSalle and Lahive & Cockfield, among others, call One Post Office home.

CBRE's Andrew Hoar, David Fitzgerald, Bill Crean, Tim Lyne and Jessica Berkey represented Sullivan & Worcester in the renewal, while JLL's Bill Barrack and Katharine Small repped owners Equity Office Properties and Morgan Stanley. The terms and exact length of the lease were not disclosed and CBRE would not disclose the price per square foot upon inquiry. GVA Thompson Hennesy & Partners Second Half 2009 Office Market Report shows that class A towers in the Financial District averages a rate of $54.32 per square foot.