215 ILCS 5/534.5
"Member Company" means any insurance company organized as a stock company, mutual company, reciprocal or Lloyds, which holds a certificate of authority to transact any kind of insurance in this State to which this Article applies, and which is either:
An insurance company shall cease to be a member company effective on the day following the termination or expiration of its license to transact the kinds of insurance to which this Article applies; provided, however, that the insurance company shall remain liable as a member company for any and all obligations, including obligations for assessments levied before the termination or expiration of the insurance company's license and assessments levied after the termination or expiration, based on any insolvency as to which the determination of insolvency by a court of competent jurisdiction occurs before the termination or expiration of the insurance company's license.
215 ILCS 5/534.5