The transition from the London interbank offered rate (LIBOR) to the secured overnight fund rate (SOFR) will continue to present challenges for private lenders and their operating and valuation teams as long as loan portfolios have a mix of LIBOR- and SOFR-based deals and as long as there are numerical differences between term SOFR and term LIBOR. The author is chairman of Valuation Research Corp. and head of its portfolio securities valuation practice.