Barclays is being sued for more than £700 million by the dealmaker who helped the bank avoid a bailout
Staveley's firm, PCP Capital Partners, is seeking £720 million -£950 million, plus interest, according to a report in the Financial Times.
The bank told the Financial Times: "We believe the claim against Barclays is misconceived and without merit and Barclays will be vigorously defending it."
The suit concerns the billions of pounds of capital injected into the bank by Middle Eastern investors in 2008 following the fall of Lehman Brothers.
Staveley helped arrange the deal between the bank and the investors, and her firm was paid millions for the service.
Although it spared Barclays from public ownership, the deals have attracted regulators' scrutiny and a fraud investigation.
The SFO has been investigating "certain commercial arrangements between Barclays Bank and Qatar Holdings" since 2012.
In 2013 the Financial Conduct Authority alleged in its own investigation that Barclays paid around £322 million ($500 million) to Qatari investors in return for a £4.6 billion ($7.15 billion) capital injection at the height of the 2008 financial meltdown.
Barclays paid a £50 million ($77 million) fine but said it would contest the findings.