American football magnate Malcolm Glazier and Dutch TV entrepreneur John de Mol have both bought up more Manchester United shares, stoking recent rumours that the club is about to be taken over.
John de Mol: In the market for Man Utd shares
Man Utd said on Wednesday that Mr de Mol, whose company Endemol created the popular 'Big Brother' television series, had increased his stake in the club from 3.5% to 4.1%.
Later the club announced that Mr Glazier, owner of the Tampa Bay Buccaneers American football team, had raised his stake from 5.9% to 8.94%.
The moves come a day after Irish horse racing tycoons JP McManus and John Magnier electrified the City by snapping up pay TV firm BSkyB's 10% stake in the club.
That transaction boosted Mr McManus and Mr Magnier's joint holding to 23.15%, triggering a flurry of speculation that the Irish duo may be preparing a full-blown takeover attempt.
Rumours of a buyout have been swirling around Man Utd, the English Premier League's richest club, since Russian billionaire Roman Abramovich's surprise takeover of Chelsea Football Club in July.
A number of wealthy investors have been steadily hoarding Manchester United shares in recent months.
Scottish mining entrepreneur Harry Dobson, and Dermot Desmond, the Irish millionaire who owns 21% of Celtic football club, have also been named as possible bidders.
Institutional investors tend to steer clear of football clubs because their financial performance is unpredictable, and most do not make enough money.
But analysts say Man Utd would make an attractive takeover target because, unlike many of its Premiership rivals, the club is free of debt and makes healthy annual profits.
It also owns one of the best-known global sports brands thanks to its long run of success on the pitch, and its roster of celebrity players.