"After a thorough investigation the SFO has concluded that there is no evidence of criminality in relation to this matter," the fraud office said in a statement following a probe lasting 2.5 years and which had been triggered following an inquiry by the BoE itself.
The SFO had in December 2014 launched an investigation into money-market auctions held by the central bank to ensure commercial banks were not left short of cash -- a particular concern during the financial crisis when the value of assets were slashed and cash liquidity levels tightened.
"The focus of the investigation was whether assistance had been provided to certain financial institutions to enable them to bid successfully for the available funding, to the possible detriment of other institutions.
"The Bank of England referred this matter to the SFO in November 2014, following its own internal investigation, and the investigation was opened the following month," it added.