NEW documents show United States treasury secretary Timothy Geithner pressed the Bank of England four years ago to make changes to the key interest rate Libor.
More than a dozen banks are under investigation over suspected rigging of the rate.
The London interbank rate, also known as Libor, influences interest rates globally, from mortgages to credit cards.
In 2008, Mr Geithner, as head of the New York Federal Reserve, sent a private email to the Bank of England governor Mervyn King and recommended six ways to enhance the credibility of the rate.
The email, which included a two-page memo, has been obtained by the Washington Post.
Read more at ABC news online.