In the larger of the two deals, Triple Net Properties has agreed to buy the 525,000-sf 525 W. Van Buren building, also known as the Congress Center, for a reported $133 million. California-based Triple Net, which has not previously been active in the Chicago market, specializes in raising money from individual investors to buy smaller and mid-sized properties, mainly office and retail. The firm has the unusual distinction of being employee-owned.

Currently the Congress Center, which was completed last year in the active West Loop submarket, is about 90% leased, with North American Company for Life and Health Insurance taking about 18% of the building, which serves as its headquarters. Other notable tenants include Amtrak, Employers Reinsurance Corp., and the U.S. Secret Service. The building was developed by a joint venture of Chicago-based Development Resources Inc. and Los Angeles-based Oaktree Capital Management; CB Richard Ellis represented the partnership in the transaction.

Also Downtown, Hamilton Partners has bought the 148,000-sf 211 W. Wacker building from SSR Realty Advisor, which was acting on behalf of Metropolitan Life and advised in the deal by Jones Land LaSalle. The building dates from the mid-1920s and was renovated in the mid-1980s. Hamilton has a sizable portfolio of suburban Chicago office properties, but this is its first Downtown acquisition. The building is 71% occupied.