by Brian Wheeler BBC News Online business reporter

United is delivering the right results on and off the pitch

The Irish horseracing magnates have bought up broadcaster BSkyB's 10% holding to take their share in United to 23%.

When news of the deal flashed across City trading screens earlier on Tuesday it predictably sent United's share price soaring.

Nothing gets investors going like the prospect of a takeover battle - particularly when the prize at stake is the world's biggest football club.

But is the speculation rooted in reality or just so much football talk?

Racehorse row

Manchester United's share price has doubled over the past year on the back of market rumours.

Manchester United shareholders JP McManus and John Magnier - 23.15% Harry Dobson, Scottish mining magnate - 6.5% Malcolm Glazer - US sports tycoon - 9.6% Landsdowne, hedge fund investor - 5.2% Jon De Mol, Big Brother creator - 3.5% Legal & General - 3% Dermot Desmond - Irish millionaire - 1.5%

And the publicity-shy Magnier and McManus have often found themselves at the centre of such gossip.

The duo have been quietly building up their holding in Manchester United for some years, through their investment vehicle Cubic Expression.

A look at who could be preparing to take over Man United At-a-glance

They have close links with United manager Sir Alex Ferguson, although the relationship has been soured in recent months by a row between Magnier and Sir Alex over the ownership of successful racehorse Rock of Gibraltar.

Under stock market rules, Cubic Expression would only have to increase its stake in United to 30% to be forced into a making a formal offer for the club.

No commercial logic?

The surprise takeover of Chelsea football club earlier this year by Russian billionaire Roman Abramovich has made anything seem possible in the world of football finance.

But most City analysts still dismiss talk of a McManus/Magnier takeover as pie in the sky.

David Pope, of Brewin Dolphin Securities, said there was little commercial logic to such a deal.

"You take over a company when either the management is underperforming, when you think there is an opportunity to improve its performance or when it is cheap.

"None of these things apply at Manchester United."

Another bidder?

Magnier and McManus would be unlikely to relish the intense media attention that would come with such a high-profile role, Mr Pope added.

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Matthew Glendinning, editor of Football Business International, said: "I don't get the feeling that they are going to buy the whole club."

He said the pair could be attempting to build up their stake so that they are in a strong position if another bidder appears on the horizon.

Or it could simply be that, with Magnier being a long-time fan of the club (McManus is apparently an Arsenal fan), they want to own a bigger piece of it.

Lee Darbyshire, editor of Soccer Investor Magazine, said: "I think it's a bit silly that every time an investor increases their stake in one of the big clubs it's seen as a takeover bid."

Analysts have also warned against reading too much into BSkyB's decision to sell up.

The broadcaster's stake in Manchester United dates back to its abortive takeover attempt five years ago.

Its decision to offload the shares now - with the price riding high - means it will have recouped almost all of its original £60m investment.

Cheaper option

Magnier and McManus's biggest potential rival for control of Manchester United is American tycoon Malcolm Glazer, owner of the Tampa Bay Buccaneers American football team.

We don't need a sugar daddy Oliver Houston, Shareholders United

Mr Glazer recently increased his holding in Manchester United to 9.66%, but he has repeatedly refused to comment on his share-buying, which has, naturally, fuelled speculation further.

Other high-profile United shareholders include John De Mol, the Dutch TV mogul behind Big Brother, Scottish mining entrepreneur Harry Dobson, and Dermot Desmond, the Irish millionaire who owns 21% of Celtic football club.

All have been linked at one time or another to possible takeover bids.

Roman Abramovich is also thought to have pondered buying Manchester United before going for the cheaper deal on offer at Stamford Bridge.

Highly profitable

No one has so far taken the step of making a formal approach to United's board.

The price, which at current market value would be £610m, is seen as being too high.

But it is surely only a matter of time before one of the existing shareholders - or a mystery bidder - is brave enough to get their cheque book out.

Because despite the best efforts of analysts to pour cold water on bid talk, Manchester United remains - uniquely in British football - a highly profitable business with good growth prospects.

It is one of the very few clubs in world football that can offer a prospective owner financial gain as well as reflected sporting glory.

Last week, it announced a 22% increase in annual profits to £39.3m, on a turnover of £173m.

"We believe it is this inherent cash generation which could make Manchester United attractive to a predator," Merrill Lynch analyst Andrew Burnett said in a report on the club's fortunes.

Fan power

But one final stumbling block for a potential buyer might be the fans, who are thought to own up to 20% of the club.

These small investors have shown little enthusiasm for a rich benefactor in the Abramovich mould and are often more interested in owning a piece of their beloved club than raking in fat dividends.

Oliver Houston, of Shareholders United, which represents about 2,000 investors, was emphatic in his rejection of a takeover, foreign or otherwise.

"We don't need a sugar daddy," he said.