MINNETONKA, MN—OneBeacon Insurance Group has renewed and expanded its lease at 601 Tower at Carlson here, bringing the 288,458-sq.-ft. property 95 percent leased.

The company has renewed, and about doubled, its 23,764-sq.-ft. lease, and now occupies a total of 45,092 sq. ft. on floors five, six and seven of 601 Tower at Carlson. The firm has been a building tenant since 2006.

The 15-story tower is in the Carlson Center master-planned office park, close to Interstates 494 and 394.The tower features a two-story marble atrium, a 55-foot rotunda and a circular staircase. Onsite amenities include a café, outdoor amphitheater and fitness center.

Tom Wille with theTampa, Fla.-based CLW Real Estate Services Group, represented OneBeacon. Mike Marinovich withCBREin Minneapolis negotiated the lease on behalf of KBS Real Estate Investment Trust II, which purchased the property in 2011.