Principal Real Estate Investors, the property-investment division of Principal Financial Group Inc., has acquired office properties in Houston and San Francisco. Bloomberg reported that Principal Real Estate, the nation’s fourth-largest institutional real estate manager, purchased Westway III, a 182,000-square-foot Class A office building in Houston, from Dienna Nelson Augustine Co. In San Francisco, Principal Real Estate purchased the office portion of the 270,000-square-foot Montgomery Washington Tower, according to a press release. The terms of the deals were not disclosed.