Deutsche Bank has agreed the biggest publicly announced longevity deal so far, a €12bn swap contract with the Dutch insurer Aegon that will protect it against the chance that its policyholders will live longer than it is expecting.

The swap, announced during Aegon's results this morning, is significant for two reasons - its size, and the fact that Deutsche says it has managed to pass its resulting exposure to longer Dutch life expectancy on to third parties - anonymous financial investors in the capital markets.