ISDA published a Guidance Note on Linear Interpolation (the “Guidance Note”) that provides further clarity to the Best Practice Statement for Linear Interpolation issued on December 18^th, 2009.

This updated Guidance Note seeks to clarify how to determine the number of calendar days corresponding to the next shorter and next longer Designated Maturities of the two known rates in certain situations, including, e.g., when ‘end-of-month’ convention applies. In addition, the Guidance Note seeks to provide further clarification for linear interpolations under the following documents: the ISDA 2013 Discontinued Rates Maturities Protocol, the IBOR Fallbacks Supplement (Supplement 70 to the 2006 ISDA Definitions) and the ISDA 2020 IBOR Fallbacks Protocol, the 2021 IBOR Fallbacks Supplement (Supplement 90 to the 2006 ISDA Definitions) and the December 2021 Benchmark Module to the ISDA 2021 Fallbacks Protocol and the 2021 ISDA Interest Rate Derivatives Definitions.