ISDA publishes market practice note on determining Initial Reference Index for CPI-U New Trades
The International Swaps and Derivatives Association (ISDA) has published a Market Practice Note (MPN) recommending a single methodology for determining the Initial Reference Index for inflation derivative transactions referencing the Consumer Prices for All Urban Consumers (CPI-U), following confirmation by the Bureau of Labor Statistics (BLS) that it will not publish the October 2025 CPI-U level. The MPN applies to ‘New Trades’ that: incorporate the 2008 ISDA Inflation Derivatives Definitions, specify an absolute number, as the Initial Reference Index, and would ordinarily have used the October Level, for transactions dated on or after 28 November 2025. ISDA recommends using the TIPS fallback methodology to generate an alternative value for the missing October level, resulting in a recommended Initial Reference Index of 325.604.