Tesco’s biggest investor, Government Pension Fund Global, has sold off a large chunk of its stake in the embattled supermarket giant.

The Norwegian group, run by Norges Bank Investment Management, sold 27 million shares in the retailer last week. Filings show that the move has now taken its stake in the retailer below the 6% mark.

Since August, Norges has sold 83.5 million shares in Tesco, worth more than £125m at the current stock price.

Tesco, which will unveil its Christmas trading performance early in the New Year, has been battling to win back customers who have defected to discounters Aldi and Lidl or switched to upmarket rivals such as Waitrose.

Shopping habits have also changed rapidly as consumers move more of their purchases online and opt for smaller top-up shops at convenience stores, rather than completing larger weekly shops at out-of-town supermarkets.

Tesco is piloting a shop-in-shop tie-up with a host of Arcadia fascias, including Burton and Dorothy Perkins, as it bids to woo back consumers.

Boss Dave Lewis, who took the helm in September 2014, has also been pushing to rebuild the retailer’s tarnished reputation in the wake of a £256m accounting scandal and repair its battered balance sheet.

Its operating profits slumped 55% to £354m in the 26 weeks to August 29, down from £779m the previous year. But Lewis hailed an improvement in like-for-like sales during its second quarter and said transaction numbers had increased 1.5% during the half year.