mortality, interest, and expense in product design
Why does a life policy cost what it costs? Strip away the marketing and almost every premium comes down to answering three questions. How likely is the insured to die and trigger a claim? What return will the insurer earn on the premiums it holds before paying out? And how much will it cost to sell, administer and service the policy? These three — mortality, interest and expense — are the pillars of life insurance product design.
Mortality sets the core cost of the promise: higher assumed death rates mean higher premiums (and they are why a 60-year-old pays far more than a 30-year-old). Interest works in the customer's favour: because premiums are invested and benefits are often paid far in the future, the present value of future claims is discounted, so a higher assumed interest rate lowers the premium today. Expenses must be loaded on top — commissions, underwriting, policy administration — turning a bare 'net premium' into the 'gross premium' you actually pay. Pricing combines all three, for instance: net premium from mortality discounted at the interest rate, plus an expense loading, equals the gross premium.
Actuaries build each assumption with prudent margins and then watch actual experience against them; the gap is exactly the source of profit or loss (and, on participating business, of policyholder dividends). The three levers also explain product personalities: term insurance is dominated by mortality, deferred whole life leans heavily on interest accumulation, and the appeal of universal and indexed products is precisely that they make these components visible and adjustable. The honest point: every life premium is a bet on three uncertain futures, which is why margins and ongoing monitoring matter.
An insurer designs a whole life product assuming mortality from a standard table, 4 percent interest, and expenses of 90 of first-year cost plus 5 percent of each premium. If actual investment returns beat 4 percent and policyholders die a bit later than the table predicts, the favorable mortality and interest margins emerge as profit — or, on a participating policy, flow back as dividends.
Mortality, interest and expense together turn a promise into a price.
These are assumptions about the future, not facts. Set them too optimistically and the product is underpriced and risky; too conservatively and it is uncompetitive — which is why insurers add margins and monitor experience rather than 'set and forget'.