摘要:In this article, we consider the evolution of the post-age-60 mortality curve
in the United Kingdom and its impact on the pricing of the risk associated
with aggregate mortality improvements over time: so-called longevity risk.
We introduce a two-factor stochastic model for the development of this curve
through time. The first factor affects mortality-rate dynamics at all ages in
the same way, whereas the second factor affects mortality-rate dynamics
at higher ages much more than at lower ages. The article then examines
the pricing of longevity bonds with different terms to maturity referenced
to different cohorts. We find that longevity risk over relatively short time
horizons is very low, but at horizons in excess of ten years it begins to pick
up very rapidly.
A key component of the article is the proposal and development of a method
for calculating the market risk-adjusted price of a longevity bond. The proposed
adjustment includes not just an allowance for the underlying stochastic
mortality, but also makes an allowance for parameter risk. We utilize the
pricing information contained in the November 2004 European Investment
Bank longevity bond to make inferences about the likely market prices of the
risks in the model. Based on these, we investigate how future issues might
be priced to ensure an absence of arbitrage between bonds with different
characteristics.