J Sainsbury shares jumped as much as 10 per cent on Thursday on talk that Qatar's sovereign wealth fund was planning a renewed offer for the British grocer after dropping a previous bid proposal in 2007.

Spokesmen for Sainsbury, Britain's third-biggest supermarket group, the Qatari Investment Authority (QIA), which owns around 26 per cent of Sainsbury, and the Sainsbury family, which own around 17 per cent and rejected the QIA's previous bid attempt, all declined to comment.

Traders reported rumours of a possible offer at 420 pence ($6.80) a share and that former Barclays banker Roger Jenkins was broking a deal.

A spokesman for Jenkins' new corporate advisory finance firm declined to comment. Jenkins left Barclays in August to set up the new company, which has a specific focus on the Middle East.

A Qatari fund abandoned a 600-pence-a-share bid proposal, worth GBP10.6 billion ($17.2 billion), in November 2007 as the credit crisis took hold.

The fund bought most of its stake, which was later transferred to the QIA, at around 575 pence a share.

Sainsbury shares, which have risen sharply on rumours of a bid from the QIA in the past, were up 8.8 per cent at 338.6 pence, valuing the business at about 6.2 billion pounds. – Reuters