Rainier Partners completed the investment in WPAS.

Rainier Partners, a private equity firm that invests in lower middle-market services businesses, completed the investment in WPAS, a third-party administration (TPA) firm specializing in multi-employer benefit plan administration. Financial terms were not disclosed. “Today’s news marks an important milestone in the history of our business. Since 1953, WPAS has been a premier service provider to Taft-Hartley multi-employer trusts. We take great pride in offering full-service trust administration to over 450,000 active members and their families across the U.S. We’re confident this partnership will pave the way for the next phase of our growth journey,” Adam Keck, WPAS CEO.