The Financial Conduct Authority (FCA) has hit Barclays PLC with a £50mln fine over a failure to disclose certain arrangements in its £4bn Qatari funding deal in 2008.
The City watchdog said the bank's conduct in the capital raise was "reckless and lacked integrity".
In 2020 three former Barclays bankers were cleared of fraud over their role in the investment.
They had been accused of funnelling £322mln in secret fees to Qatar in exchange for emergency funding at the height of the financial crisis.
Mark Steward at the FCA said: "At the height of the financial crisis in October 2008, Barclays paid hundreds of millions of pounds in fees to certain Qatari investors so that they would contribute new capital."
"Barclays did not inform the market and shareholders about these matters as required."
"Barclays’ failure to disclose these matters was reckless and lacked integrity and followed an earlier failure to disclose fees paid to Qatari investors in June 2008. There was no legitimate reason or excuse for failing to disclose these matters, certainly no basis for doing so because of the financial crisis" he said.
Shares in Barclays were 1.8% lower at 142.8p.