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Math 479 / 568 Casualty Actuarial Mathematics. Fall 2014 University of Illinois at Urbana-Champaign Professor Rick Gorvett Session 13: Reinsurance II – Exposure Rating and Increased Limits Factors October 14, 2014. Reinsurance Pricing. Pro rata reinsurance
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Math 479 / 568 Casualty Actuarial Mathematics Fall 2014 University of Illinois at Urbana-Champaign Professor Rick Gorvett Session 13: Reinsurance II – Exposure Rating and Increased Limits Factors October 14, 2014
Reinsurance Pricing • Pro rata reinsurance • Straightforward pricing, since a percentage • Consider adequacy of primary pricing • Excess reinsurance • Price is generally specified as a percentage of “subject premium” • Two traditional approaches to pricing: • Experience rating • Exposure rating
Exposure Rating • Allocation of primary premium to different “layers” of coverage • Consider adequacy of primary premium • Depends upon: • Attachment point and limit of reinsurance layer • Primary premiums at different policy limits • Increased limits factors (ILFs)
ILFs • Consider a loss severity (size per claim) distribution • For example: exponential distribution:
ILFs (cont.) • Specifically, consider an exponential distribution with a mean of 20:
ILFs (cont.) • Suppose that the primary insurer writes a “basic limits” policy, with a limit of 25 per occurrence • Notation (Y = insurer’s payment):
ILFs (cont.) • One item of interest: • Another item: what is the expected size of a claim paid by the insurer?
ILFs (cont.) • Consider different policy limits written by the primary insurance company: Policy LimitE[Y]“ILF” 25 14.27 1.000 50 18.36 1.287 100 19.87 1.392 Unlimited 20.00 1.402
Exposure Rating • Suppose basic limits (BL) premium = $100. Policy LimitPremium 25 (BL) 100.00 50 128.70 100 139.20 Unlimited 140.20
Exposure Rating (cont.) • Consider 50 x/s 50 layer: • Worth 139.20 - 128.70 = 10.50 • But this value can also be determined via ILFs: 100 (1.392-1.287) = 10.50 • Exposure rating involves using quantitative relationships between limits to allocate premium to different layers
Examples • What proportion of the primary premium on a 100 limit policy should go to the 50 x/s 50 reinsurance layer? • Suppose you determined that primary premiums are, in general, 10% inadequate. What proportion of the 50 limit policy premium should go to the 25 x/s 25 layer?
Caveat • A big issue here is the nature of the ILFs. • How are expenses handled? • How is risk load handled? • A reinsurer might want to use loss-only ILFs, without risk load, to determine the loss portion of the layer, then determine the final reinsurance premium by incorporating its own expenses and risk load. • Thus, adjustments may need to be made to results associated with situations like the examples.