The Bank of America Merrill Lynch UK Pension Plan has insured benefits for 915 pensioner members in a £400m buy-in with Scottish Widows.
The bank's largest pension scheme made the step as part of a long-term de-risking journey, with the deal helping to improve its long-term funding position.
The scheme was advised by Aon and its Bulk Annuity Compass platform, while legal advice was also provided by Linklaters.
Scheme chairman Peter Gibbs said the deal had been secured on "favourable terms".
"We are delighted with the advice and support provided by Aon and Linklaters throughout the transaction process, and to extend the bank's existing relationship by entering this long-term partnership achieving greater security for members in the plan."
The deal was completed in 2018, when the insurer secured around £1.8bn of benefits. It follows a £140m buy-in with a Peugeot scheme, also completed last year, and came ahead of a £690m buy-in with a QinetiQ scheme, conducted this year - both were announced last week.
The insurer's head of origination and structuring, Matt Wilmington, said: "We are proud that the trustees have chosen to insure members' benefits with us as part of their ongoing de-risking plan. Working collaboratively with Aon, Linklaters, and the trustees, we were able to deliver an attractive price and complete the transaction within weeks of being selected as the trustees' preferred adviser."
Just over £3.6bn of bulk annuities have been announced so far this year across eight deals with at least four insurers.
Aon head of bulk annuities John Baines said: "It was a pleasure to support the trustees and Bank of America Merrill Lynch in completing the buy-in. As a financially sophisticated trustee board, understanding the additional security that could be provided to members through an insurance solution was a particularly important aspect of this transaction.
"Their understanding of market dynamics allowed the trustees to navigate a busy market and quickly lock into great pricing."
In its most recent annual funding update, dated 31 December 2017, the scheme reported a £143m surplus on an actuarial basis, with £1.5bn of liabilities and £1.7bn of assets.
Aviva Life & Pensions has concluded an £875m buy-in with its own staff pension scheme, following on from a similar transaction last year.
Just Group has completed a £74m pensioner buy-in with the UK pension scheme of a US-listed engineering business.
The Smiths Industries Pension Scheme has secured a £146m buy-in with Canada Life in its fourth bulk annuity and its sponsor’s tenth overall.
The Prudential Staff Pension Scheme has entered into a £3.7bn longevity swap with Pacific Life Re, insuring the longevity risk of over 20,000 pensioners.
The Baker Hughes (UK) Pension Plan has secured approximately £100m of liabilities through a buy-in with Just Group.