A source close to US buyout firm Kohlberg Kravis Roberts & Co has said the company is not mulling a takeover bid for UK supermarket firm J Sainsbury, despite media reports to the contrary. A UK newspaper reported at the weekend that KKR, which earlier this year expressed interest in acquiring UK supermarket chain Safeway, had enlisted Archie Norman, a former chief executive of Asda, to look into the possibility of KKR making an offer for J Sainsbury.