In a statement today, the embattled retailer said the overstatement of its expected profit for the six months to 29 August 2014 was largely due to the accelerated recognition of commercial income and delayed accrual of costs.
In a conference call for investors, group chief executive Dave Lewis said Tesco has contacted the financial regulator, which will investigate the matter.
It has also suspended “a number of people”, including four senior executives.
Tesco shares dropped 11% to 205.55p shortly after the opening bell following the shock announcement.
Tesco has also asked Deloitte to undertake an independent review, and will give an update when it releases its interim results, which will now be on 23 October.
Lewis said: “We have uncovered a serious issue and have responded accordingly. The chairman and I have acted quickly to establish a comprehensive independent investigation.
“The board, my colleagues, our customers and I expect Tesco to operate with integrity and transparency and we will take decisive action as the results of the investigation become clear.”
This latest profit warning is the third Tesco has issued this year: Lewis took over as chief executive in July following the departure of Philip Clarke after a profit warning. In August, the group’s shares dropped 10% after it issued another and slashed its dividend by 75%.
The supermarket’s shares are down 38% year to date.
