Secured Overnight Financing Rate (SOFR) is a secured interbank overnight interest rate and reference rate established as an alternative to LIBOR, which is published in a number of currencies and underpins financial contracts all over the world. Because LIBOR is derived from banks' daily quotes of borrowing costs, banks were able to manipulate the rates through lying in the surveys. Deeming it prone to manipulation, UK regulators decided to discontinue LIBOR.

As of 2021, SOFR is seen as the likely successor of LIBOR in the US. SOFR uses actual costs of transactions in the overnight repo market, calculated by the New York Federal Reserve. With US government bonds serving as collateral in the borrowing, SOFR is calculated differently from LIBOR and is considered a less risky rate. The less risky nature of SOFR may result in lower borrowing costs for companies.

Unlike the forward-looking LIBOR (which can be calculated for 3, 6 or 12 months into the future), SOFR is calculated based on past transactions, which limits the rate's predictive value on future interest rates. In addition, SOFR is overnight, whereas LIBOR can have longer tenors.