ABy Admin
Jul 25'24

Exercise

The exposure is split into three geographic regions: region A, region B and region C. The following accident year 1 data is available:

Region Current relativity Exposure Weight Earned Premium at Current Rates Projected Ultimate Loss
A 1.125 30% 421,875 375,000
B 1 50% 625,000 500,000
C 1.25 20% 312,500 300,000

Suppose the following is true:

  • Policies are annual.
  • Loss cost inflation is 4% per annum.
  • There are no fixed or variable underwriting expenses.
  • The insurer is targeting a profit percentage of 20%.

Using the loss ratio method, determine the rate change % for region A.

  • +27.58%
  • +28.15%
  • +30.56%
  • +31.17%
  • + 32.97%
ABy Admin
Jul 25'24

The midpoint of the experience period is 07/01/CY1 and the midpoint of the forecast period is the end of calendar year 3; hence, the trend factor equals 1.042.5 = 1.103 and the projected ultimate inflation adjusted losses for accident year 1 equals $1,296,025. Given a targeted profit percentage of 20% and an aggregate earned premium at current rates for accident year 1 equaling $1,359,375, the loss ratio method gives an overall change factor of 1.3111. The loss ratio method gives the following indicated rate differentials/relativities

Region [math]i[/math] [math]\operatorname{R}_{I,i}/\operatorname{R}_{C,i} [/math] [math]\operatorname{R}_{I,i}[/math]
A 1.1111 1.25
B 1 1
C 1.3021 1.6276

Given a targeted overall change factor of 1.3111, the change factor for the base rate equals

[[math]] 1.3111 \cdot \frac{\sum_i w_i \operatorname{R}_{C,i}}{\sum_i w_i \operatorname{R}_{I,i}} = 1.1877. [[/math]]

Hence the base rate should be increased by 18.77%. The rate change factor for region [math]i [/math] equals 1.1877 multiplied by [math]\operatorname{R}_{I,i}/\operatorname{R}_{C,i} [/math]:


Region [math]i[/math] Rate Change
A + 31.97%
B +18.77%
C +54.65%
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