Allied Universal, the 140,000-worker, $4.5 billion (yearly sales) building-services company based in Conshohocken, Pa. and Santa Ana, Calif., says it has purchased Apoll0 International, a 3,400-worker, $88 million-a-year rival based in Walpole, Mass. and New York.

Sellers include Apollo's founders, Dennis Crowley and Dick Ryer, who founded the firm after serving together in the U.S. military in Vietnam during the war. Price not yet disclosed.

Though it's less than 3 percent of Allied's size, Apoll0 adds the high-end security services that Allied CEO Steve Jones says corporate clients need: Besides uniformed security officers and front-desk staff, that includes "investigations, special operations, competitive intelligence, risk management consulting, vulnerability assessments and other security/asset protection programs."  

Apollo markets to colleges, factories and warehouses and tech facilities, among other clients.

Allied, whose predecessors include Philadelphia's old SpectaGuard, is owned by a string of private-equity firms led by France's Wendel and including Warburg Pincus and Partners Group.