The British billionaire behind Tottenham Hotspur Football Club has swooped on Bear Stearns, seizing a 7 per cent stake in the troubled American investment bank.

Joe Lewis, who made his fortune trading in global currency markets, has quietly bought the stake for $860 million (£424 million) in separate tranches over the past two months.

Mr Lewis grabbed the stake when the investment bank was at its most vulnerable.

In June, Bear Stearns became one of the first public casualties of the sub-prime mortgage crisis in America when it admitted that two hedge funds it ran had lost $1.5 billion collectively and was forced to close them.

Since the beginning of the year, America’s fifth-largest bank has lost about 30 per cent of its stock market value, fuelling speculation that it may be vulnerable to a takeover bid.

Yesterday’s swoop raised questions on Wall Street as to whether Mr Lewis has accurately identified the bottom of the market, or whether there may be more losses ahead across the US banking sector.

Investment banks have yet to reveal their losses from the credit crisis this summer, with third-quarter figures due in the next few weeks.

The acquisition makes Mr Lewis the largest single shareholder in the bank, ahead of Putnam Investment Management, with 6 per cent, and the holding of James Cayne, chief executive of the bank, who controls 5.8 per cent.

It is not clear whether Mr Lewis intends to increase his stake in the bank or whether he is hoping for a takeover approach for the whole group.

News of Mr Lewis’s move comes as it emerged that other US banks were also seeking to take advantage of the credit turmoil by raising funds to buy up cheap debt.

Sources said Goldman Sachs was raising Goldman Liquidity III, a roughly $1.5 billion fund to invest in different types of debt, including corporate and leveraged assets trading below par but underpinned by sound valuations.

Lehman Brothers is also understood to be marketing a $3 billion debt fund and a number of hedge funds, including GLG Partners and Oaktree Capital, are also raising new funds to go out and buy up mountains of debt.

Several private equity firms, including TPG Capital, Apollo and Blackstone, are also thought to be talking to investors about new debt funds.

They are understood to be particularly keen to invest in the billions of dollars of debt backing a string of huge buyouts that took place at the height of the M&A boom but which banks can now not sell because investors have shied away from high-risk leveraged loans.

In a filing yesterday to the US Securities and Exchange Commission, the regulator, Mr Lewis said that he had built his stake using five investment vehicles, all based in the Bahamas.

According to Forbes magazine’s rich list, Mr Lewis is estimated to be worth about $2.5 billion.

He became well known in the 1990s when he pounced on Christie’s, the auctioneer, taking a near-30 per cent stake and tried to take the company private.

Mr Lewis’s family part own Enic, the sports and media group. Enic owns 66 per cent of the shares of Tottenham Hotspur, the Premier League football club.

Chris Whalen, of Institutional Risk Analytics, said: “What the investment shows is that Bear Stearns looks like good value at this level. Bear Stearns is a sound bank, I’m not worried about their future.

"The banks you should be worrying about are the ones who have still to ’fess up about their exposure to sub-prime. The banks who have owned up about their exposure and been forthright about it are going to be fine.

"The real problem is the lack of certainty in the market, the lack of hard data to do with the rest of the banks.”

Bear Stearns and Mr Lewis’s main investment vehicle, Tavistock, were unavailable for comment.

Mr Lewis is reported to spend part of the year in Orlando, Florida, and some of it in the Bahamas, having left the UK in 1979.

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