Sainsbury's shares took a tumble in mid-morning trading after the British grocer revealed that its chief executive, Justin King, would be leaving the group after 10 years as its leader.
Sainbury's stock price fell by over 2% to 349.30p as of 1045 GMT after King confirmed that he would depart after the group's annual shareholder meeting on 9 July this year.
King said that "the departure decision was entirely mine" and that he has "not talked to anybody else about any other job."
Sainsbury unveiled commercial director Mike Coupe as King's successor while the group's Chairman David Tyler revealed that chief financial officer John Rogers did not put himself forward for the chief executive job.
Sainsbury's underlying profit has almost trebled under King's decade long reign and the group is Britain's second largest player behind market leader Tesco.
Coupe joined Sainsbury in 2004 has been tipped to be the favourite to succeed King for years. He was also a former director of Big Food Group and Iceland.
On 8 January, Sainsbury revealed that Christmas sales were boosted by its Taste the Difference luxury food range, as well as customers redeeming loyalty points and shopping online.
According to Sainsbury's third quarter trading update, sales at stores open over a year rose 0.2%, excluding fuel, in the 14 weeks to 4 January. Total third quarter sales rose 2.7%, excluding fuel.
In the seven days prior to Christmas, Sainbury's reported its busiest ever trading week, with more than 28 million transactions.
The group revealed that 23 December marked its busiest day of the year as customers spent nearly £17m (€20.5m, $28m) in one hour, at one point.