Southampton could be the latest club to be taken over by an American after the club confirmed a takeover approach.
A statement to the Stock Exchange said: "We have received, and are considering, a preliminary approach."
Speculation has linked Microsoft co-founder Paul Allen, the world's 19th richest man, with the Saints.
A source close to Allen told the Daily Mail: "He sees Southampton as a sleeping giant, a family-supported club with traditional values."
The Stock Exchange statement added: "The board note the recent rise in the company's share price.
"The board's consideration is at an early stage and there is no guarantee that any offer will be forthcoming."
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Allen owns the Seattle Seahawks NFL franchise and the Portland Trailblazers NBA outfit and the source said: "We see the value in taking the brand global."
Allen retains his interest in Microsoft as an investor in Dreamworks animation studio, and is a backer of the SpaceShipOne project to launch commercial space flights.
Forbes magazine estimates his fortune at £9bn.
Several ultra-wealthy Americans have snapped up English football clubs, headed by the Glazer family at Manchester United, George Gillett and Tom Hicks at Liverpool, and Randy Lerner at Aston Villa.
American billionaire Stan Kroenke is involved in a battle to take over Arsenal.
Championship club Southampton have been searching for new investors since Michael Wilde replaced Rupert Lowe as chairman last summer.
Millionaire property developer Wilde himself resigned earlier this year after failing to attract investment.