What is the difference between an insurance company and a reinsurance company?

5 "Reinsurance is a special form of insurance obtained by insurance companies to help spread the burden of indemnification. A reinsurance company typically contracts with an insurance company to cover a specified portion of the insurance company's obligation to indemnify a policyholder in the event of a valid claim. This excess insurance, as it is called, enables the insurance companies to write more policies than their reserves would otherwise sustain since [it] guarantees the ability to pay a part of all claims. The reinsurance contract is not with the insured/policyholder. When a valid claim is made, the insurance company pays the first level insured, and the reinsurance company pays the insurance company. The reinsurance company's obligation is to the insurance company, and the insurance company vis-a-vis the reinsurer is thus the insured, or more appropriately the 'reinsured.' " (Excess & Cas. Reinsurance Ass'n v. Insurance Com'r, Etc., supra, 656 F.2d at p. 492, emphasis added.)