The London Interbank Offered Rate (LIBOR) is an interest rate average calculated from estimates submitted by the leading banks in London. It is the primary benchmark for short-term interest rates globally and is used as a reference rate for transactions in offshore Eurodollar markets. LIBOR is calculated for five currencies and seven borrowing periods ranging from overnight to one year and is published each business day by Thomson Reuters. Many financial institutions, mortgage lenders, and credit card agencies set their own rates relative to it. At least $350 trillion in derivatives and other financial products are tied to LIBOR.

LIBOR was based on five currencies including the U.S. dollar, the euro, the British pound, the Japanese yen, and the Swiss franc, and served seven different maturities—overnight/spot next, one week, and one, two, three, six, and 12 months. Currently, only the overnight, one-, three-, six-, and 12-month USD LIBOR rates and the three-month GBP LIBOR rate are published.

LIBOR has been subject to manipulation, scandal, and methodological critique, making it less credible today as a benchmark rate. It has been replaced by the Secured Overnight Financing Rate (SOFR) on June 30, 2023. However, LIBOR is still used as a benchmark for many other interest rates at which business is actually carried out. U.S. Dollar LIBOR is the most used reference rate to determine the interest rates in financial contracts, including consumer loans, such as adjustable-rate mortgages, reverse mortgages, home equity lines of credit (HELOCs), student loans, and credit cards.