In 2012, HSBC agreed to pay $1.92bn (£1.2bn) – the largest fine of its kind at the time - to the US government to settle the money laundering probe in a deal known as a "deferred prosecution agreement".
Under the terms of the agreement, the US justice department agreed to drop criminal charges into the bank’s transfer of billions of dollars for countries such as Iran, in return for changes to its business practices.
During the probe, HSBC was also accused of helping Mexican drug cartels launder money through the US financial system.
According to media reports, a US Congressional report into HSBC’s financial settlement has surfaced, detailing how George Osborne and the FCA, then known as the Financial Services Authority (FSA), lobbied the US authorities against prosecuting the bank overs fears it would lead to market volatility.
"George Osborne, chancellor of the Exchequer, the UK's chief financial minister, intervened in the HSBC matter by sending a letter to Federal Reserve chairman Ben Bernanke ... to express the UK's concerns regarding US enforcement actions against British banks," said the report.
Furthermore, the testimony said the FSA “hampered” the US government's investigations which “influenced” the Justice Department’s decision not to prosecute the bank.