Universal Protection Service, a division of Universal Services of America and a portfolio company of Warburg Pincus and Partners Group, has acquired Guardsmark. The companies together create the largest U.S.-owned security company. Terms of the transaction were not disclosed.

Based in Memphis, Tenn., Guardsmark has more than 125 offices serving more than 400 cities in the U.S., Canada, Puerto Rico and the U.K. The company is led by Ira A. Lipman, founder, CEO and chairman, and has sought to cultivate a culture of customer service for more than 52 years. Guardsmark has grown organically without acquisition for 38 years.

Headquartered in Santa Ana, Calif., Universal Protection Service provides a mix of traditional security services with systems and technology. Universal operates nationwide in more than 100 locations, including Puerto Rico and U.S. Virgin Islands. The combined company will employ approximately 60,000 security professionals across the U.S. and Canada.

 Bank of America Merrill Lynch acted as financial advisor to Guardsmark. Credit Suisse acted as financial advisor to Universal Protection Service. Cleary, Gottlieb, Steen & Hamilton LLP acted as legal counsel Universal Protection Service. Fried Frank LLP acted as legal counsel to Guardsmark.