Guardsmark was a major provider of security services in North America, Puerto Rico and the United Kingdom.
Founded in 1963, Guardsmark was the fourth largest security company and the only major provider privately held by one family.
The family-run company employed more than 18,900 people with reported revenues of more than $510,000,000.00 in 2005.
The firm marketed itself as offering more rigorous screening of applicants, including in many states, the requirement that applicants submit to a polygraph examination and a drug screen for illicit and prescription drugs before hiring.
Guardsmark was sold to and absorbed by Universal Protection Service in 2015.