English Annuities in the Late 1700's

In the late 1700's, the English government wanted to raise some money. To do this, they decided to sell lifetime annuities. Such annuities are a promise to pay an individual a fixed amount per year for the remainder of his or her life. For example, a $100 annuity would pay an individual $100 per year for as long as he lived.

The English government based the price of their annuity on the assumption that the average life expectancy at birth was about 14 years. (When they issued such annuities in 1540, they assumed 7 years.) The annuities were sold at the same price to everyone who wanted one.

What do you think happened?

To help you answer the above, here is a little more information about the situation. At this time, the idea that you could estimate the life expectancy of a population was just being developed. (Actually, it was being rediscovered, as the Roman jurist Ulpian had created a set of ``life tables'' 1400 years earlier.) Edmund Halley (of comet fame) had just completed some estimates and found that it would be ``an even Wager that...a Man of 30 may reasonably expect to live between 27 and 28 [additional] years.''

A very interesting account of the history of probability and risk analysis is contained in a book by Peter Bernstein, Against the Gods: The Remarkable Story of Risk. These concepts emerged from the gambling of aristocrats and ended up being incorporated in to all aspects of modern life, from insurance to Wall Street (perhaps they have come full circle?).