Massachusetts' residual market mechanism is the Massachusetts Workers' Compensation Assigned Risk Pool (MWCARP).   In accordance with M.G.L. Chapter 152, Section 65C, the Commissioner of Insurance has designated the Massachusetts Workers' Compensation Rating and Inspection Bureau of Massachusetts (WCRIBMA), the licensed rating organization for Massachusetts, to administer the assigned risk pool for workers' compensation insurance.

The Massachusetts Workers' Compensation Assigned Risk Pool was created by statute to provide a means for Massachusetts employers, who could not obtain coverage in the voluntary market, to satisfy their obligations under M.G.L. Chapter 152.  The Massachusetts Workers' Compensation Assigned Risk Pool must provide coverage to any employer who is entitled in good faith to workers compensation insurance.