USD LIBOR, or the U.S. Dollar London Interbank Offered Rate, was a benchmark interest rate that represented the average rate at which major global banks estimated they could borrow unsecured U.S. dollars from one another in the London interbank market. For decades, it served as one of the world's most widely used reference rates for pricing financial products and contracts.

USD LIBOR was published daily for several borrowing periods, known as tenors, including overnight, one month, three months, six months, and twelve months. Financial institutions, corporations, and investors relied on these rates to determine interest payments on products such as adjustable-rate mortgages, business loans, syndicated loans, floating-rate bonds, and interest rate derivatives. At its peak, trillions of dollars in financial contracts worldwide referenced USD LIBOR.

However, following the global financial crisis of 2008, concerns emerged that the underlying market for unsecured interbank lending had become less active. Investigations also uncovered that some banks had manipulated LIBOR submissions to benefit their trading positions or improve their perceived financial health. These events significantly reduced confidence in the benchmark.

As a result, regulators initiated a global transition away from LIBOR. Most USD LIBOR settings permanently ceased publication in September 2024, marking the end of its use as a primary benchmark. In the United States, the Secured Overnight Financing Rate (SOFR) became the preferred replacement. Unlike USD LIBOR, SOFR is based on actual transactions in the U.S. Treasury repurchase market, making it a more transparent and reliable benchmark. The replacement of USD LIBOR represents one of the most significant reforms in modern financial markets.

USD LIBOR was a benchmark interest rate that estimated the average cost of unsecured U.S. dollar borrowing among major international banks. It became one of the most widely referenced interest rates in global finance and played an essential role in determining payments on mortgages, business loans, floating-rate bonds, and derivatives. The rate was published daily for several loan periods, making it a standard reference across financial markets. However, investigations uncovered manipulation by certain banks, while the underlying interbank lending market continued to shrink. These issues reduced the benchmark's reliability and prompted regulators to introduce a replacement. The United States adopted the Secured Overnight Financing Rate (SOFR), which is based on actual overnight lending transactions secured by Treasury securities. Today, USD LIBOR has been discontinued, and SOFR has become the preferred benchmark for most newly issued U.S. dollar financial contracts.