Blackstone, CPP, SMBC-backed TowerBrook, a private equity firm, agreed to invest in Langan, a civil engineering company. Financial terms were not disclosed. "Over the years, many investors have expressed great interest in Langan, and we have evaluated multiple options during this process. We found TowerBrook's reputation and resources best suited to help Langan achieve our strategic goals. TowerBrook excels at partnering with professional services firms. They understand the value of our people and our culture, which differentiated TowerBrook from the other investors that were under consideration," David T. Gockel, Langan President and CEO.