Houston office buildings made up nearly 30 percent of the value of Parkway Properties' latest selling spree. Since January 2015, the company has sold $624 million in properties, including $179 million in Houston, according to a quarterly earnings report released Monday. The sales are part of the Orlando-based company's strategy to focus on bigger office buildings. The sales leave Parkway Properties with a portfolio that is 92.7 percent leased overall.