The position of Chris Ronnie, the chief executive of JJB Sports, was in doubt last night after he admitted that his 27.5 per cent stake in the struggling retailer was now owned by the liquidators of Kaupthing, the collapsed Icelandic bank.

Mr Ronnie, a friend of Mike Ashley, who controls Sports Direct, was effectively appointed to the job on the back of the stake purchase.

He told JJB’s board yesterday that Guro Leisure, a company in which he has a 50 per cent holding, had lost control of the JJB stake some time last year after a margin call from Kaupthing Singer & Friedlander (KSF), the UK unit of the Icelandic bank. He bought his stake in 2007 but last night was unable to say when it was seized.

In a statement, JJB said that Mr Ronnie had told the company he was “not aware of the date or place of the relevant transaction or of the price per share in respect of the transaction”.

The extraordinary admission came on the back of an investigation into JJB’s affairs instigated by Sir David Jones after his appointment two weeks ago as executive chairman. The inquiry is being led by Herbert Smith, the company’s lawyers, and Lazard, its financial adviser.

The revelation that KSF had a call on the stake after lending the money to Mr Ronnie to buy it has also caused surprise, prompting comparisons with David Ross, who resigned from the board of Carphone Warehouse after it emerged that he had secretly mortgaged his 20 per cent holding in the company he co-founded.

The source of the money used by Mr Ronnie to buy the stake has long perplexed the market, leading to frequent speculation – always firmly denied – that the £190 million purchase of the original 29 per cent stake, later diluted to 27.5 per cent by share issues, had been bankrolled by Mr Ashley. At the time of the purchase from Dave Whelan, the former footballer and JJB founder, the company said only that the shares had been acquired by “a joint venture vehicle formed by Icelandic financial group Exista and Chris Ronnie”. Exista had close ties with Kaupthing.

JJB said that it had been informed by KSF’s Isle of Man offshoot (KSFIOM) that it held 23.3 per cent, while its own investigation had established that KSF itself held another 2.8 per cent. It said that, according to PricewaterhouseCoopers (PwC), KSF’s liquidator, a further 1.3 per cent stake had been sold on to an unidentified party.

In the formal stock market notification of the transfer, PwC said it had “discovered that KSFIOM did not make the appropriate notifications when it became entitled to exercise the voting rights in relation to these shares”.

Companies have an obligation to notify the market of such transactions within four working days and can face stiff penalties for breaking the rules.

A spokesman for JJB said: “Sir David and the board of JJB are undertaking a thorough investigation to understand what is behind today’s announcement. They want to bring transparency to the company’s affairs.”

One adviser close to the situation described it as “a bloody mess” but said that Sir David, the former chief executive of Next, was “determined to get to the bottom of this”.

If Mr Ronnie’s reputation may have been damaged, his wealth certainly has. The shares were bought at 275p but in recent months the price has dived to 13¾p.

Analysts suggested that if Mr Ronnie was forced to step down, the day-to-day running of JJB could pass, at least temporarily, to Peter Williams, the former Selfridges chief executive, who was appointed an executive director at the same time as Sir David’s elevation to the chairmanship.

Mr Ronnie has spent most of his career in the sports retail business. Before joining JJB in June 2007, initially as deputy chief executive, he worked for Mr Ashley at Sports Direct. He has also worked at Umbro and Sports Division, the retail chain owned by Sir Tom Hunter, before its sale to JJB in 1998.

Mr Ronnie was unavailable for comment.

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