Britain’s biggest charity, the Wellcome Trust, has amassed a near-£4bn war chest of cash amid fears of a stock market meltdown.

The endowment fund, best known for operating the Wellcome Collection museum in London, said it was keeping about £3.7bn on the sidelines as “dry powder” in the hope of buying cheap stocks if markets tanked.

The charity added that with stock markets at “all-time highs”, it felt that keeping cash on hand made sense, given stocks were too expensive to buy.

The charity said it had already used some of the war chest to buy stocks following Donald Trump’s US tariff blitz in April, when global markets nosedived.

However, the window quickly closed as markets rebounded after Mr Trump backed away from his most extreme tariff plans.

The Wellcome Trust is not alone in turning to cash.

Warren Buffett, the legendary US investor, also built up a $378bn (£280) cash pile, among the largest ever held by his Berkshire Hathaway conglomerate – equivalent to over a third of its market value.

The Welcome Trust’s annual report said: “Public equity markets look at least fully priced on any metric and expensive in a longer-term historical context.

“This is especially true in the USA, but other markets have seen valuation multiple expansion too.”

The charity was established in 1936 by Sir Henry Wellcome, a pharmaceutical entrepreneur who founded the business that would eventually become GSK.

It’s £40bn of assets makes it one of the largest investment funds in Britain, currently run by chief investment officers Lisha Patel and Fabian Thehos.

The Wellcome Trust invests heavily in scientific research, and spent £1.9bn in 2024 funding trials on issues as diverse as plague treatments in Madagascar and postnatal depression.

Overall, 8.9pc of its portfolio was held in cash, well above a historic average of 3pc to 5pc. Just over 41pc of its investments were in public markets, with 34.1pc in private equity, including buyout and venture capital funds.

A further 7pc was held in hedge funds, and 8.2pc was invested in property. Overall, its portfolio returned 10.2pc in 2025, up from 5.2pc the previous year. This was below the FTSE 100, which made investors a 21pc return last year.

It added that falling interest rates, rising geopolitical uncertainty and stock markets “at or near record levels across very long periods” meant it was battling a “complex investing environment”.

“Our performance this year has been reasonably strong,” the charity said, “though with expectations for future real returns inevitably trending down.”

The Wellcome Collection is based in Euston and saw 403,000 visitors last year.

Several years ago, the museum, which holds more than a million objects amassed by its founder, closed one of its key exhibitions, branding it “racist, sexist and ableist”.

The museum explained that its exhibition was “problematic” as it told a story “in which disabled people, black people, indigenous peoples and people of colour were exoticised, marginalised and exploited – or even missed out altogether”.

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