JD Sports shares have plunged after the company's largest investor sold holdings worth £177 million.

The retailer's stock slid 10.2% to 721.9p in early trading after majority owner Pentland Group confirmed the major shares sale.

Pentland, which also owns sportswear brands such as Speedo and Berghaus, said it sold 24 million shares in the company at 740p each.

READ MORE: Sir Brian Souter to step down as Stagecoach chairman

The group will now have a 55% stake in the FTSE 100 retailer, having first purchased a 57.5% holding in the business in 2005.

Chairman Stephen Rubin said: "Pentland is committed to remaining a long-term majority shareholder in JD at the same time as growing our portfolio of sports, outdoor and fashion brands through organic investment and acquisitions.

"Today's share sale enables us to further this strategy by realising a small portion of our shareholding in JD to fund future investment activity, as well as increasing the free float to meet the increasing interest expressed in JD by other shareholders."

The owner of Zara has seen profits surge as the fashion retailer shrugged off the demise of the UK high street.

Inditex, the Spanish owner of the chain, said an increased focus on its online platform helped to cut costs and boost profitability over the first three quarter of 2019.

READ MORE: Retired plumber calls for political action on pension debts

The retail group said that gross profits increased 8% to €11.5 billion (£9.7 billion) for the nine months to October 31.

Sales across the group jumped 7.5% to €19.8 billion (£16.7 billion), with trading steady across the period.

It said it now expects like-for-like sales to grow by between 4% and 6% during the full year.

The company, which also has brands including Bershka and Pull & Bear, said it has been resilient against challenges in the sector due to tight control of inventory, which has helped it avoid major discounting.

Pablo Isla, executive chairman of the group, said the positive figures were a result of "the excellent performance of the entire Inditex team, whose commitment is enabling the delivery of continued sustained growth in our integrated stores and online model".

Attempts by Amazon to buy a minority stake in online food delivery business Deliveroo were in doubt on Wednesday as the competition watchdog warned it could launch full-scale investigation into the deal.

The Competition and Markets Authority (CMA), which has been investigating the deal since it was first announced in May, said it had serious concerns that competition could be stifled.

READ MORE: Robert Morris creates new £32m business park on former furniture factory site

Andrea Gomes da Silva, executive director at the CMA, said: "There's a real risk that it could leave customers, restaurants and grocers facing higher prices and lower quality services ... because the significant competition which could otherwise exist between Amazon and Deliveroo would be reduced."

The concerns for the CMA include that the deal could discourage Amazon from re-entering the restaurant food delivery sector - having previously launched and closed its Amazon Restaurants business a year ago.