trustbuster
noun [ C ]
LAW, FINANCE informal (also trust-buster); (trust buster) uk/ˈtrʌstˌbʌstər/ usa person or organization that works to prevent illegal arrangements between companies:
He was hired as a federal trustbuster by the Justice Department.
trustbusting
noun [ U ] (also trust-busting)
The extent to which consumers have benefitted from trustbusting is hard to prove.
Several companies were targetted in the government's latest trust-busting exercise.