Transcript Handout 2
Numerical Examples –
Adjustable Features
Jeanne Lee Ying
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Basic Steps
Build aggregate loss distribution
Lognormal is a common distribution used for aggregate loss
distribution
Model frequency and severity separately
Usually assume the independence between frequency and
severity
Apply specific treaty adjustable features to the loss distribution curve
generated or to each simulated year
Reasonability check
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Numerical Examples
Profit Commission
Loss Ratio Corridors
Loss Ratio Caps
Swing Rate
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Profit Commission Example
A Casualty Prorata Treaty
Subject Premium: 50M
Loss Ratio: 70%
Weighted average based on all year on level loss ratios
Ceding commission: 22%
Brokerage: 0%
Profit Commission: 30% after 15% of reinsurer’s margin
Profit Commission formula =
0.3 x (premium-loss-expense-reinsurer’s margin)
What is the expected profit commission for the deal?
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Modeling A Lognormal
Distribution
Model a Lognormal Aggregate Distribution
Parameters: Loss Ratio (mean): 70%, Standard Deviation (SD): 20%
CV (Coef. of Varitation)= Standard Deviation / Mean = 0.2 / 0.7 = 0.2857
Sigma = SQRT (LN((CV^2 +1)) = 0.28
Mu = LN(mean) – (Sigma^2)/2 = 17.3
Determine loss ratios with their associated probability
EXCEL Function Lognormdist (X, Mu, Sigma)
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Profit Commission Example
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Profit Commssion -Key
Observation
Cost of expected profit commission (1.2%) does not equal to the
cost of profit commission at the expected loss ratio (0%)
For Casualty lines, historical data may not reflect a full range of
possibilities
Adjusting CV using judgement to account for more
variability
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Loss Corridor Example
A Casualty Pro Rata Treaty
Loss Ratio: 70%
Weighted average based on all year on level loss ratios
Ceding commission: 22%
Brokerage: 0%
A Loss Corridor between 80%-90% loss ratio
What is the expected loss ratio net of the corridor?
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Loss Corridor
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Loss Ratio Cap Example
A Casualty Pro Rata Treaty
Loss Ratio: 75% with standard deviation of 30%
Ceding commission: 22%
Brokerage: 0%
A Loss Ratio Cap at 110%
What is the expected loss ratio net of loss ratio cap?
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Loss Ratio Cap
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Modeling Frequency and Severity
Separately
A Casualty Excess of Loss Treaty
Assume frequency and severity are independent
Simulate Severity to the Layer
Simulate on level frequency
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Swing Rated Example
A General Liability Excess of Loss Treaty
750K xs 250K Layer with 10M Subject Premium
Premium is adjusted based on 100/80 loading factor subject to a
minimum rate of 10% and a maximum rate of 25%
Expected burn cost: 18%
Adjusted Premium= Minimum of
Layer Loss x 100/80 + Minimum Rate x Subject Premium
Maximum Rate x Subject Premium
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Swing Rated Example
A General Liability Excess of Loss Treaty
For each year, simulate Claim Count Using Poisson. In this case,
Lamda=4.4
For each claim count, assign a loss severity based on simulation of
Lognormal or Pareto distribution. We used a 5 parameter truncated
Pareto distribution.
For this example, we simulated 1000 years
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Simulation Summary
# of
Layer
Total
Claim
Loss
Adj Prem
1
1
1
49k
1061k
49k
2
1
176k
1220k
176k
3
0
0k
1000k
4
3
198k
1247k
52k
5
1
393k
1491k
393k
6
6
1156k
2445k
7
2
824k
8
2
Yr
2
3
4
5
6
35k
110k
282k
229k
2k
26k
21k
596k
2030k
664k
160k
1289k
2500k
1003k
286k
-----
-
-
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-
-
7
996
2
1239k
2500k
852k
387k
997
7
3029k
2500k
90k
48k
83k
706k
1003k
95k
1003k
998
8
4122k
2500k
1003k
522k
440k
421k
78k
1003k
381k
999
2
399k
1498k
206k
193k
1,000
5
393k
1492k
130k
112k
101k
16k
34k
1772M
2236M
Total
Expected Loss Ratio
8
275k
79%
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