452 CMR, § 5.05
A parent corporation may add a subsidiary to its license only at the time of the original license application or when said license is renewed or on 60 days notice, if the self insurer amends its most recent filings, unless it is a subsidiary without employees, in which case, ten days notice is required. The parent corporation must be the sole owner of any subsidiary or other legal entity it wishes to include under its license. In applying for an original license, or a license renewal, which would cover one or more subsidiaries, the parent corporation shall provide information on each subsidiary on a form prescribed by the Department. The parent corporation must guarantee the liability of their subsidiaries on a form prescribed by the Department which must be signed, sealed and duly accepted by the Department. Where there is a parent/subsidiary combination, the requirements of 452 CMR 5.04 shall apply to the combined entity.
452 CMR, § 5.05