SOFR stands for Secured Overnight Financing Rate, which is a benchmark interest rate that reflects the cost of borrowing cash overnight collateralized by Treasury securities. It is calculated and published daily by the Federal Reserve Bank of New York and is intended to replace the LIBOR (London Interbank Offered Rate) as a reference rate for financial transactions. The SOFR is based on actual transactions in the overnight Treasury repo market, making it a more reliable and accurate benchmark rate compared to the LIBOR, which is based on estimates and has been subject to manipulation scandals.