Asda’s owner, Walmart, has signed a deal to offload nearly £4bn of the UK grocer’s pension liabilities, clearing the path for a stock market flotation.

Walmart and Asda’s pension trustees have agreed a deal with Rothesay Life – a specialist in corporate retirement schemes – worth £3.8bn.

The deal, first reported by Sky News, could mark an important step towards a demerger and subsequent stock market float following Asda’s failed attempt to merge with Sainsbury’s.

Under the terms, Rothesay would be responsible for paying the retirement benefits of around 12,000 members of the Asda Group Pensions Scheme. The supermarket giant has made a one-off payment of £800m into the scheme with a long-term objective of a full buyout of the plan.

The scheme is separate to the Asda Pension Plan, a defined contribution scheme that provides ongoing pension arrangements to the majority of Asda workers.

The grocer’s boss Roger Burnley said: “This transaction is an excellent outcome for our scheme members – and for Asda and Walmart. We have supported the scheme over many decades through significant cash contributions.

“That funding, combined with strong stewardship by the scheme’s trustees, has resulted in the very positive situation where the scheme can now be transferred to an A+ rated insurance company, Rothesay Life – de-risking the scheme and providing long term, sustainable support for its members.”

Richard Phillips, chairman of trustees, added: “This is great news for members. We have had many years of support from Asda and Walmart, and careful management by the Asda pension team with the help of our advisers. Together we have now secured our members’ benefits through Rothesay Life, an insurer which has strong financial credentials and a track record of excellent customer service.”

Back in May, Walmart international boss Judith McKenna told Asda’s staff that it was mulling a move to float its UK division.

She said: “Walmart does not have a one-size-fits-all approach to operating its international markets, but a consistent focus on strong local businesses powered by Walmart.

“While we are not rushing into anything, I want you to know that we are seriously considering a path to an IPO – a public listing – to strengthen your long-term success.”

Observers are seeing the pensions move as a part of the process to return the grocer to the stock exchange.