Seeking to expand its corporate headquarters at 175 Berkeley Street as well as its overall presence in Boston, Liberty Mutual announced today that it has signed a purchase and sale agreement to buy the properties located at 10 St. James Avenue and 75 Arlington Street in the Back Bay from Millennium Partners. The companies did not disclose the closing date or financial terms of their agreement. Purchase of the properties means Liberty Mutual will own the entire block between Arlington and Berkeley Streets and St. James Avenue and Stuart Street. Last October Liberty Mutual purchased 330 Stuart Street, a building that is directly across the street from its headquarters. "Growth in our operations worldwide necessitates increased space in our corporate headquarters," said Edmund F. Kelly, Liberty Mutual Group chairman, president and CEO. "This purchase, as well as being a good investment, will provide Liberty with considerable flexibility for future expansion of our home base in Boston for many years." Liberty Mutual, ranked 111th in the Fortune 500, has 1,870 employees in its Back Bay offices, and more than 3,200 in 30 locations throughout Massachusetts. Completed in January 2001, 10 St. James Avenue is a 19-story modern office building. Built in 1913, 75 Arlington Street is an adjacent 10-story historic building that was refurbished in 2001. The properties connect to Liberty Mutual's Back Bay headquarters at 175 Berkeley Street. Liberty Mutual is a major tenant in the properties, which are fully leased by a roster of high-quality tenants. The company plans to continue to lease the property to office and retail tenants. Millennium Partners is well known for developing and managing first class, mixed-use office, retail and residential buildings. "In selling this building to Liberty Mutual we are gratified to know that a company with a commitment to Boston similar to ours will continue to own and operate this great building," said Tony Pangaro, principal, Millennium Partners - Boston. Liberty Mutual's ties to Boston and the region extend beyond its insurance operations and Back Bay address. The Liberty Mutual Foundation supports Greater Boston non-profit causes in arts and culture, education, and health and human services with contributions of more than $4 million annually. Along with its philanthropic giving, many of the company's executives are members of the board of directors of area non-profits. As of December 31, 2004, Liberty Mutual Group had $72.4 billion in consolidated assets and $19.6 billion in annual consolidated revenue. Liberty Mutual ranks 111th on the Fortune 500 list of largest U.S. corporations based on 2004 revenue. It is the eighth-largest personal lines writer and fifth-largest commercial lines writer in the U.S. based on 2004 direct written premium. Liberty Mutual Group today employs more than 38,000 people in nearly 900 offices throughout the world.