These notes assume the reader knows the general principles on which bonus reserve valuations are made.

The essential idea is to value as a liability the amounts the office will be liable to pay as sum assured, bonus and expenses, setting of f as an asset the amounts the office will receive—the office premiums. The valuation must be based on really accurate estimates. We must use the mortality we think will prevail and the interest we think can be relied on in respect of existing business. Admittedly bonus is uncertain—a valuation of future bonus does not guarantee it—but the valuation must be as accurate as possible. The bonus allowed for will be realised if the conditions assumed prevail in future.

The table of mortality is usually a standard table to which the experience of the office may be regarded as an approximation, but need not necessarily relate to the same class of life. The essential qualification of any table for use must be that it is a real approximation to the likely future experience of the office for which it is used.