Captive insurance companies are now popular for tax planning in addition to risk management. In response, the IRS has developed an increasingly sophisticated set of standards for determining what is insurance over the past few years. The latest development in the IRS’ analytical framework for captives is Revenue Ruling 2008-8, which defines the tax treatment of “rent-a-captives,” known officially as segregated cell captives. The ruling holds that if a rent-a-captive satisfies the tax requirements of an insurance company, it will be treated as a standalone insurance company despite its lack of separate legal status.