The founding family of WM Morrison is said to be considering taking the supermarket group private, according to market reports on Wednesday.The Morrison family, who are thought to hold around 9-10% of the UK grocer, have spoken to a number of private-equity firms to gauge their interest, according to Bloomberg.The news agency, which quoted people close to the matter, said that the Morrisons had contacted funds such as CVC Capital Partners, Carlyle Group and Apax Partners.A potential buyout of WM Morrison, valued at a market capitalisation of around £5.7bn, would be at least £7bn, according to Bloomberg's sources.WM Morrison is the fourth largest chain of supermarkets in Britain, behind Tesco, Sainsbury and Wal-Mart-owned Asda.BC