Tesco may ditch its auditor PricewaterhouseCoopers after accounting problems that led to a £263m shortfall in its books, according to reports, although the troubled supermarket group stayed silent.Tesco is due to appoint a new auditor in 2016 but may bring forward the change to next year following the overstatement of its expected profits two months ago, the reports said.The supermarket group is facing a Serious Fraud Office inquiry into the accounting problems, which have also been scrutinised by PwC's rival Deloitte in a separate review ordered by Tesco.The group is also said to have hired Deloitte to work with its accountancy department to prevent a recurrence of the issues.Tesco, which is understood to have employed PwC for 31 years, declined to say anything. A spokesman said: ""We don't comment on rumour or speculation."It comes as Kantar Worldpanel data earlier this week showed Tesco with the worst sales fall in the sector in the 12 weeks to 9 November, down 3.7%, although the retail research group noted that the rate at which it was losing market share had slowed.