• Corridor Self-Insurance Retention, also known as the “bikini deductible”, is a self-insurance layer that separates the primary risk layer, whether insured, self-insured or captive financed, from the layer directly above the primary. It was first used in health insurance by incorporating a deductible (a true deductible, not a self-insured withholding (SIR)) between a first dollar health plan and a primary health insurance that exceeds a primary health insurance policy. The structure is reminiscent of a bikini because there is some protection at the bottom and top, but nothing in between. Corridor SIR companies moved from health insurance to property and casualty applications as risk managers, brokers and creative underwriters of excess insurance looked for more sophisticated methods of allocating and financing risk. As a rule, the SIR level of the corridor is not funded. It is used to reduce the cost of (or provide access to) excess or umbrella insurance while freeing the insured from having to fund expected losses. It is also used in structured insurance schemes. Corridor SIRs can be designed to cover non-aggregated case limits or a combination of case limits and cumulative limits. A typical corridor SIR will include per-case limits, possibly subject to annual aggregation, depending on the risk and excess insurance price.