Leicester City will hope for FA Cup glory against Chelsea on Sunday just as the real tale emerges of the extraordinary investment by their Thai owner, Vichai Raksriaksorn. He has spent £53m in a quest to achieve Premier League football, which again appears distant this season.

Like a lower-league Roman Abramovich, Raksriaksorn has showered money on his project since buying the club in the summer of 2010. Sven-Goran Eriksson was hired in October of that year, then fired 12 months later for failing to achieve promotion, while £11m has been spent on the salaries of a band of players that includes Darius Vassell, Jermaine Beckford and Kasper Schmeichel, not all of whom have impressed.

The Foxes are 11th in the Championship, 16 points from the automatic promotion places. Nigel Pearson, who succeeded Eriksson as manager, speaks of attaining a place in the play-offs – currently two wins away – in guarded tones. "Its still mathematically a possibility," he says. "We're not a million miles away but of course our inconsistencies this season have made it very difficult for us to make any inroads into the league. There'll be twists and turns between now and the end of the season, there's no doubt about that."

The latest £26m of the £53m injected by Raksriaksorn, who owns Leicester through the holding company Asian Football Investments, is a loan at 8% and not interest-free as, say, Abramovich has done with Chelsea. Asked about this dependence, Pearson says: "We are fortunate that we have very wealthy benefactors who have invested an awful lot of money not only in the squad but in the infrastructure of the club. I think that's important to recognise.

"But certainly [as] financial fair play is looming, its something I'm sure the club will address. But in terms of the stability of our club we're fortunate to have owners who have made a long-term commitment.

"There are an awful lot of football clubs in the country whose finances are not probably what they would like. But I think we have the stability here in terms of the business infrastructure to be able to deal with those sorts of figures. And it's not just a case of writing them off, it's managing it and I think the club will have a very sensible business plan moving forward."

Clubs who rely on benefactors can be precarious. The model relies on an Abramovich or a Raksriaksorn not walking away and demanding their equity back instantly. And Chelsea's Russian and Leicester's Thai have proved heavy investment's price is impatience. The latest accounts, published at the start of the month, state of Eriksson: "The club fell frustratingly short of the play-offs and an inconsistent start to the season has led to Sven leaving the club," when the Foxes were only two points from a play-off place, four better off than now.

For Raksriaksorn, £53m should have bought instant promotion and after Eriksson left by "mutual consent" Pearson may not be too confident of what the summer could bring.

He is calm, though, about how failure to achieve promotion this season may affect the club's approach. Pearson says: "Well financial fair play is not implemented this year but I think with any club there's got to be different strategies moving forward. So it's important to plan for the future with an eye on different scenarios and that's something that the club has done."

Regarding Leicester's financial ethos following a record £15.2m loss last season, the chief executive, Susan Whelan, says: "The club's strategy of investing in a strong squad to fight for a promotion place has led to increases in staff costs. We continue to invest in both the playing squad and the capital assets of the club, but we are also working hard to increase our commercial revenue."

Rangers, Portsmouth, and Port Vale all offer the latest lesson in what financial infirmity can do to proud clubs. So far £53m has achieved only Sunday's FA Cup quarter-final with Chelsea – which Leicester are favourites to lose – and not much else apart from a loan they will have to repay one day.

As Schmeichel, who was at Notts County when the club was threatened with being wound up, says: "It's not just about the money, consistency is what we need here. The gaffer's got his ideas and I think with a full pre-season he's going to get what he wants out of us. It's still a work in progress for him.

"I'm not going to get too involved in that type of conversation [on finances]. I'm not really qualified to, but obviously you've seen a lot of things going on with debt in football at the moment, with Rangers and Portsmouth, so things like that are a worry. I don't know the ins and outs of everything but I'm confident that the club know what they're doing."