Kelso & Co., a middle-market private equity firm, has acquired Align Capital Partners‘ interest in WilliamsMarston LLC, a differentiated, national provider of complex accounting, tax, and valuation advisory services.

Under its ownership of Align, WM increased its professional team to over 225 and has expanded existing client relationships, added new clients and completed six add-on acquisitions.

“Together with WM leadership, we significantly exceeded our investment objectives,” said ACP managing partner Chris Jones. “The WM team has been an outstanding partner for ACP and our investors, and we are incredibly appreciative of their efforts and accomplishments over the past two years. The Firm has achieved remarkable growth while maintaining its steadfast commitment to its brand, clients and people. All of us at ACP are excited to watch WM’s continued growth and success.”

William Blair, Houlihan Lokey and BellMark Partners acted as financial advisors to WM, and Kirkland & Ellis LLP served as legal counsel to the Firm.