The Bank of England has asked Britain's market regulator, the Financial Conduct Authority, to investigate a jump in the pound a minute before the central bank said it would keep interest rates on hold.
"We are aware of the incident and are looking into it," the auhtority said.
The bank confirmed it had asked the authority to look into the incident. Earlier, the central bank held interest rates at 0.75 per cent.
Its Monetary Policy Committee voted 7-2 to keep rates unchanged.
Last month the bank launched an investigation into claims that some investors had eavesdropped on press briefings moments before they were broadcast, giving a split-second advantage to high-speed traders.
"Following concerns raised with the bank, we have recently identified that an audio feed of certain of the bank press conferences, installed only to act as a back-up in case the video feed failed, has been misused by a third party supplier to the bank since earlier this year to supply services to other external clients."
The authority is also investigating.
