Barclays Bank faces another £50m in fines from the Financial Conduct Authority for acting recklessly and without integrity towards shareholders.
According to a notice issued by Barclays it entered deals with Qatar Holding LLC in June and October 2008.
However, it did not make public the £322m in fees payable which accompanied these deals, nor did it disclose that it had entered into the latter deal.
As a result, on 13 September the FCA issued warning notices against the bank including a financial penalty of £50m for breaching listing principles demanding the lender act with integrity towards shareholders and prospective shareholders.
Barclays has now said it will contest this fine.
The Serious Fraud Office is also in the early stages of investigating the agreements.
Barclays has admitted the SFO investigations could not only result in financial penalties and reputational impact but also in possible criminal liability.
This latest threat to Barclays coffers came a month after the lender announced it would issue £5.8bn in shares to help plug a £12.8bn gap in its capital adequacy.
Two months ago it emerged that the bank would be hit with another £300m fine in civil penalties for manipulating electric energy prices.
This fine came only 12 months after the Financial Services Authority fined Barclays a then-record £59.5m, part of a package of £290m of penalties from UK and US regulators for manipulating the London interbank offered rate and Euro interbank offered rate.