"Any changes to BBA Libor should be in response to market evolution and not as a result of a knee-jerk reaction," the BBA said in a report, which it issued following consultation with banks and Libor users such as central banks, derivatives traders and exchange operators. The BBA began the consultation in early June, when it announced its intention to find ways to boost confidence in Libor.

The decision to reject changes, the report said, stemmed in part from concerns that altering Libor could sow confusion in the market and cause legal problems, given the vast number of contracts based on the current Libor definition. Libor, which is set every day in 10 different currencies and 15 maturities, forms the basis for payments on some $350 trillion in loans and other financial instruments.