Prudential Retirement has completed around $2.6bn (£2bn) of reinsurance contracts for UK pension scheme longevity risk since the start of the year, it has disclosed.
The US life insurer - a branch of Prudential Financial - said the cover secures the risk of around 16,000 pensioners and the volume represents an "unprecedented start to the 2019 UK pension risk transfer market".
The reinsurance of UK insurers' longevity risk frees up capacity to carry out further bulk annuity transactions, with around £3.6bn of deals announced so far this year.
Prudential Financial head of longevity reinsurance Amy Kessler said the uncertainty around Brexit was also driving demand in the market.
"Pension schemes that can afford to de-risk have raced forward in the opening months of 2019, taking advantage of the window before Brexit to reduce their risks and lock in gains," she said.
"Brexit brings increasing levels of uncertainty that could wash away recent market gains and funding improvements, putting de-risking out of reach for those with lower hedge ratios. But with funding at the highest levels in a decade, pensions are de-risking at an unprecedented pace."
Kessler cited research from Aon Hewitt which found the average FTSE 100 defined benefit scheme was 100.1% funded on an accounting basis as of 29 March. This has been helped by an increasing number of schemes hedging their liabilities, with over £1trn using liability-driven investment according to XPS Pensions.
Prudential Financial vice-president Christian Ercole added mortality trends were also benefitting scheme funding and providing "impetus to de-risk".
Last month, the Continuous Mortality Investigation (CMI) - published by the Institute and Faculty of Actuaries (IFoA) - revealed mortality improvements had again declined with lower life expectancies found for both males and females who turned 65 in January this year, compared to last year.
The Electricity North West Group of the Electricity Supply Pension Scheme (ESPS) has invested in an £805m pensioner buy-in with Scottish Widows.
Zurich has agreed to insure £800m of longevity risk for the pensioners of a FTSE 100-sponsored pension scheme.
The ESAB Group (UK) Limited Pension & Life Assurance Scheme has purchased a £255m full buy-in with Rothesay Life, covering benefits for all 900 members of the scheme.
The value of UK bulk annuity deals is set to quadruple in the 2020s when compared to this decade, Mercer has predicted.
Greater regulatory focus on covenant, holistic risk management, and long-term targets has helped proactive schemes approach their endgames earlier, says Adolfo Aponte.