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πŸ”Ž Attitudes toward risk

Β Risk AverseRisk NeutralRisk Loving
Who?Most people*Crazy
MUDecreasingConstantIncreasing
Shape Risk averse utility graph: concave curve showing U(1,000), U(2,500), U(4,000) with EU below U(2,500), Line of Expected Utilities, EV = 2,500 Risk neutral utility graph: straight line showing U(1,000), U(2,500), U(4,000) with Line of Expected Utilities equal to utility curve, EV = 2,500 Risk loving utility graph: convex curve showing U(1,000), U(2,500), U(4,000) with EU above U(2,500), Line of Expected Utilities, EV = 2,500
CE vs EVCE<EVCE \lt EVCE=EVCE = EVCE>EVCE \gt EV

* Insurance companies, high frequency professional traders, and professional gamblers are slightly risk averse, but almost risk neutral

Insurance companies, as described above, tend toward risk neutrality. It is rational for them to do so because of the law of averages. If you take a large number of small bets and you evaluate each bet in a risk neutral way, then in the long run, you’ll tend to make money. They evaluate their costs, as described earlier, using EV. The EV providing an insurance policy is known as the β€œactuarially fair” premium for the policy.

Risk averse utility curve (concave) showing U(1,000), U(2,500), EU, U(4,000) with Line of Expected Utilities below the curve, demonstrating that EU is less than U(EV) at EV = 2,500

Sidebar ( YOU ARE NOT RESPONSIBLE FOR THIS, BUT IT IS IN THE BOOK)

Is this person willing to pay more or less than the actuarially fair amount for their insurance policy?
The person is willing to pay 4Kβˆ’CE4\text{K} - CE.
It costs 4Kβˆ’EV4\text{K} - EV to provide the insurance.
Because CE<EVCE < EV, the person is willing to pay a premium, above the actuarially fair amount for their insurance.
Because their willingness comes from risk aversion, we refer to this extra amount that they will pay as their risk premium.
We can calculate the risk premium as

MaxPremiumβˆ’ActuariallyFair=(Bestβˆ’CE)βˆ’(Bestβˆ’EV)=EVβˆ’CE\text{MaxPremium} - \text{ActuariallyFair} = (\text{Best} - CE) - (\text{Best} - EV) = EV - CE

The fact that people in general are risk averse implies that they will pay a positive risk premium for insurance. Because the Actuarially fair amount is how much it costs to provide insurance, this means that insurance companies can provide insurance profitably to risk averse people.

Payout is Bestβˆ’remainingΒ wealth\text{Best} - \text{remaining wealth}.
EV of payout is Bestβˆ’EVΒ ofΒ remainingΒ wealth=Bestβˆ’EV\text{Best} - EV \text{ of remaining wealth} = \text{Best} - EV

See also: πŸ“– Textbook on Insurance