A longevity swap transfers the risk of pension scheme members living longer than expected to another provider.
The swap covers around half of the scheme's liabilities. Axa said the deal would provide long term protection to around 11,000 existing pensioners in the scheme against costs resulting from members living longer than initially expected.
Stephen Yandle, chairman of Axa UK Pension Trustees Limited which governs the fund, said: "By significantly de-risking the scheme, this will benefit all our DB scheme members and will not affect any payments to members as they will continue to receive their pension as normal. This is a very positive step in providing additional security of members' pensions."
James Mullins, partner and head of buy-out solutions at Hymans Robertson, said the market for longevity swaps represents "excellent value at the moment" due to high reinsurer appetite for UK longevity risk.
"It is very telling that five insurance companies - the experts in managing risk - have now chosen to transfer a large proportion of their pension scheme longevity risk to third parties," he said.
"It is also interesting that the three most recent of these transactions involved the pension scheme passing their longevity risk directly onto reinsurance companies, rather than using a third party intermediary. We believe this trend will continue."