A Tesco supermarket in Glasgow, Scotland.
Jeff J Mitchell I Getty Images
Britain's accounting watchdog, the Financial Reporting Council (FRC), said on Monday it had launched an inquiry into PwC over its auditing of Tesco's 2012, 2013 and 2014 accounts.
In October Tesco, Britain's biggest retailer, said it had misstated its profits by 263 million pounds ($411 million), compounding a disastrous run of profit warnings.
PwC were not immediately available for comment.
The watchdog has powers to sanction accounting firms and their staff for failing to apply book-keeping rules properly.