The bank received the investment as the financial crisis was unfolding, but whether or not it violated the Foreign Corrupt Practices Act is now the subject of investigations by both the Justice Department and the Securities and Exchange Commission, The Wall Street Journal reported Wednesday.
Essentially, regulators want to know if agents of the bank used bribes to get the Qatar Investment Authority to invest billions of dollars in the bank during a financial crisis.
When the investment was announced, Barclays said it had hired the QIA to play an "advisory" role in the Middle East. Later, the bank said it was paying $384 million for the services.
The bank said it was conducting its own investigation and cooperating with officials, whose investigation mirrors an inquiry started earlier this year by Britain's Financial Services Authority.
In its third quarter statement Barclays also gave notice the Federal Energy Regulatory Commission is preparing to charge the bank with manipulating prices for electricity from 2006 to 2008 in western U.S. states.
Barclays has been besieged with regulatory problems this year. Regulators this summer said the bank had paid $450 million to settle charges by U.S. and British agencies that it had attempted to manipulate the London inter-bank offered rate or Libor, a benchmark rate used to set interest rates on trillions of dollars in personal and business loans.