3.2 How Life Insurance Works: Mortality, Interest, Reserves
Key Takeaways
- The three pricing factors are mortality (cost of dying), interest (investment earnings), and expenses (loading); together they set the gross premium.
- Mortality tables, such as the Commissioners Standard Ordinary (CSO) table, predict deaths per 1,000 at each age and drive the cost of insurance.
- Assumed interest reduces premiums because the insurer expects investment earnings on reserves before claims are paid.
- The legal reserve is the insurer's liability set aside to guarantee future claims; level premiums create reserves because early overcharges are banked.
- The net amount at risk is the death benefit minus the policy reserve and shrinks as cash value grows.
Life insurance works on the law of large numbers: although no one can predict when a single person will die, an insurer covering millions of similar lives can predict the number of deaths in a group with great accuracy. Pooling premiums from many insureds lets the company pay the claims of the few who die. The price each insured pays is built from three factors.
The Three Premium Factors
| Factor | What it measures | Effect on premium |
|---|---|---|
| Mortality | Cost of claims (deaths per 1,000) | Higher mortality raises premium |
| Interest | Earnings the insurer expects on invested premium | Higher assumed interest lowers premium |
| Expenses (loading) | Commissions, taxes, administration | Higher expenses raise premium |
Net premium = mortality minus interest. Gross premium = net premium plus the expense loading. The exam frequently asks which factor lowers cost: only interest reduces premium, because the company expects to earn investment income before claims come due.
Mortality and the CSO Table
Insurers price the cost of insurance using a mortality table such as the Commissioners Standard Ordinary (CSO) table, adopted by states for reserve and nonforfeiture calculations. The table lists expected deaths per 1,000 lives at each age. Mortality rises with age, so the pure cost of one year of coverage rises every year.
Worked example: If a mortality table shows 2 deaths per 1,000 at age 40, and each policy carries a $100,000 death benefit, expected claims per insured equal (2 / 1,000) x $100,000 = $200. That $200 is the mortality cost for the year, before adding interest credit and expense loading.
Why Level Premiums Create a Reserve
Because mortality cost rises each year, a policy priced on pure yearly cost would become unaffordable in old age. Instead, whole life uses a level premium: the policyholder pays the same amount every year. In the early years the level premium is higher than the true cost of insurance; in later years it is lower. The early overcharges are not profit. They are invested and accumulate as the legal reserve.
The Legal (Statutory) Reserve
The reserve is a liability on the insurer's balance sheet. It is the amount that, with future premiums and assumed interest, is expected to be exactly enough to pay all future claims. State law requires insurers to hold this legal reserve, which is why traditional carriers are called legal reserve companies. The reserve is an accounting/solvency concept; the cash value the policyowner can borrow or surrender is closely related but is the policyowner's side of that build-up.
Net Amount at Risk
As the reserve and cash value grow, the insurer's true exposure shrinks. The net amount at risk is:
- Net amount at risk = Death benefit - Reserve (cash value)
Worked example: On a $100,000 whole life policy with a $30,000 reserve, the net amount at risk is $100,000 - $30,000 = $70,000. The insurer charges mortality only on the $70,000 it actually stands to lose. At death the company pays the $100,000 face amount; in effect the policyowner's own cash value funds part of it and the insurer's pure insurance funds the rest.
Participating vs. Nonparticipating
If an insurer assumes conservative mortality, interest, and expenses and then experiences better results, a participating (par) policy returns the surplus to owners as a policy dividend. Dividends are treated as a return of overcharged premium and are therefore generally not taxable until they exceed total premiums paid. A nonparticipating (non-par) policy pays no dividends but typically charges a lower guaranteed premium.
Worked Dividend Example
Suppose a par whole life policy charges a $1,200 annual gross premium and, after favorable mortality and investment results, the insurer declares a $180 dividend. Because the $180 is treated as a refund of overpaid premium, it is not taxable, and the policyowner's net cost falls to $1,020 for the year.
Common dividend options include taking cash, reducing the next premium, leaving the dividend to accumulate at interest (the interest is taxable), buying paid-up additions of extra coverage, or buying one-year term. Only the interest earned on accumulated dividends is taxable; the dividend itself is a return of premium until cumulative dividends exceed cumulative premiums paid.
Which of the three premium factors, when assumed to be higher, REDUCES the premium an insurer charges?
A $250,000 whole life policy has accumulated a reserve (cash value) of $60,000. What is the net amount at risk to the insurer?
Worked Numeric: Net Amount at Risk Over Time
The insurer's true exposure on a permanent policy is the net amount at risk (NAR) = death benefit minus cash (reserve) value. As cash value grows, the insurer's pure-insurance exposure shrinks.
Worked example: a $100,000 whole life policy with $30,000 cash value carries a NAR of $100,000 - $30,000 = $70,000. At $100,000 - $0 in early years the NAR is nearly the full face; near maturity, as cash value approaches the face amount, NAR approaches zero and the policy 'endows.'
This is why level premiums overcharge in early years (building the reserve) and undercharge later: the reserve plus interest funds the rising mortality cost while the shrinking NAR keeps the insurer's risk manageable. Mortality, interest, and expense are the three pricing factors - higher assumed interest lowers premium, higher assumed mortality or expense raises it.