Employers located in other states but conducting business and/or employing workers in Massachusetts must have an applicable Massachusetts workers' compensation insurance policy for their employees. Coverage will not be valid if Massachusetts is not endorsed in section 3A or 3C of the information page of a workers' compensation insurance policy. If Massachusetts is not endorsed in section 3 A of the information page but coverage exists in Massachusetts under section 3C, an employer's insurance carrier must file a Form 154 with the Office of Investigations upon request of said office.
452 CMR, § 8.08