A Boston real estate investor sold a pair of Oak Brook office buildings for $24 million, not much more than it paid for them more than 11 years ago.

TA Associates Realty sold One and Two Oak Brook Place, a 179,000-square-foot complex, to American Landmark Properties last month, according to DuPage County property records. American Landmark, a Skokie-based landlord, was part of the investor group that sold the Willis Tower for $1.3 billion last year to Blackstone Group. Representatives from TA Associates and American Landmark did not respond to requests for comment. The sale shows how the suburban office market, which crashed after the financial crisis, has rebounded in recent years, as rents and occupancies have risen and investors have returned to the market. TA paid $23.5 million for the buildings at 2301 and 2311 W. 22nd St. in February 2005, a couple years before the real estate market peaked, and likely would have taken a loss if it sold the properties a few years ago. American Landmark financed the acquisition with a $15.6 million loan from Prime Financial Partners, according to Chicago-based mortgage broker Cohen Financial, which arranged the loan. The property is 94 percent occupied, according to Chicago-based Cohen. Each three-story building has more than 90,000 square feet, and the complex was 94 percent occupied when the deal closed, Cohen Financial said. Tenants include Advocate Health Care and Taylor Precision Products, a maker of housewares including the Rabbit corkscrew.