The Financial Reporting Council (FRC) said it has closed a probe into PwC's actions in signing off Barclays' compliance with rules on holding money and assets on behalf of clients between 2007 and 2011.
"The executive counsel to the FRC has concluded that there is not a realistic prospect that a tribunal would make an adverse finding against PwC LLP in respect of the matters within the scope of the investigation," a regulatory statement read.
A spokesperson for PwC said: "We cooperated fully during the FRC 's thorough investigation and are pleased that the FRC has closed it without any further action.”
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Today's announcement follows a similar move by Britain's top accounting watchdog in 2013 over PwC's sign-off of Barclays Capital.
Regulators launched a number of investigations into whether auditors have complied with rules on signing off of so-called "client money audits".
The sign-offs were of particular interest as segregating client and bank money was a key issue during the credit crunch and associated banking crisis almost 10 years ago.