SHARES in Sports Direct slumped more than 15 per cent as the company announced a delay in the publication of its results.

Mike Ashley’s retail empire admitted to complexities in integrating department store chain House of Fraser, which it bought earlier this year.

Analysts were surprised at the move to hold back the results, with some also pointing to potential concerns outwith the House of Fraser portfolio.

Sports Direct had been due to update the stock market on Thursday, but this will now be pushed back until some time between July and August, it said.

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In a statement, Sports Direct said its auditors, Grant Thornton, need more time to sign off the accounts.

It said: “The reasons for the delay are the complexities of the integration into the company of the House of Fraser business, and the current uncertainty as to the future trading performance of this business, together with the increased regulatory scrutiny of auditors and audits.”

It said that “these factors have led to a need for the company to compile more information than in previous years”, adding: “Sports Direct would also note that increased regulatory scrutiny is leading to longer lead times generally for the completion of audits.

“Sports Direct believes its accounts and their audit to be at an advanced stage.

“However, there are a number of key areas to conclude on which could materially affect the guidance given in Sports Direct’s announcement of December 2018.”

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In December it was suggested that House of Fraser could break even in the 2019/20 financial year.

Analysts also raised questions over wider results.

Russ Mould, AJ Bell investment director, said: “Sports Direct’s explanation that auditors Grant Thornton need more time to make sure the numbers are transparent, following a Financial Reporting Council review of the 2018 figures, makes sense but investors will be more concerned by two other factors cited for the delay.

“One is the integration process regarding August 2018’s acquisition of House of Fraser for £90 million.

“Worse still, Sports Direct says that a number of issues could mean the earnings guidance given last December for the full-year to April could prove too optimistic.

“Since Mr Ashley gave guidance both including and excluding House of Fraser some eight months ago, this implies that trading in the core retail business has also disappointed.”

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Nick Bubb, an independent retail analyst, said: “There may be something in what Sports Direct say about company audits generally taking longer because of increased regulation - Superdry’s results were delayed by the complexity of its onerous store impairment provision - but the company hasn’t updated the City since its interims in December and House of Fraser is clearly a disaster area, so this is a serious situation.”

Peel Hunt retail analysts Jonathan Pritchard and John Stevenson warned: “House of Fraser is clearly in a degree of disarray, it would appear that the finance department is under-staffed to cope with the array of acquisitions, and we are also concerned about the direction of the core business.”

Earlier this year, House of Fraser revealed an underlying pre-tax loss for the first six months of the year of £31.5m on revenues of £70.1m.

Shares opened down 26.4p at 237p, falling by as much as 15% on the news on Monday.