SuperGroup, the owner of the high street Superdry clothing brand, has said major system upgrade problems will wipe up to £9 million from its annual profits.

The company is upgrading warehouse management systems at its Barnwood site in Gloucestershire, in a bid to improve capacity. But it said today that problems with the migration have led to a “significant” reduction in the amount of stock reaching its UK stores, with many sizes entirely unavailable.

In order to address warehousing requirements in the interim, SuperGroup has commissioned a separate temporary distribution site. It estimated the cost of this and the lost sales at £6 million to £9 million for the year.

“The group has reacted swiftly to resolve the situation,” SuperGroup said in a statement. “Whilst the majority of the system issues have been rectified, some are still ongoing.”

“It is anticipated that our distribution capability will have returned to normal levels of operation and have been fully upgraded with additional capability and efficiency in November.”

The news alarmed SuperGroup investors, who sent the company’s share price into a 29 percent nosedive to 715 pence. In July, SuperGroup had reported an underlying profit of £37.8 million as it worked on a fast expansion programme of stores.