This paper studies the determinants of materiality disclosure among International Integrated Reporting Council (IIRC) Pilot Program companies implementing the IIRC Framework. In other words, it studies which variables influence the way in which such companies provides information about their materiality determination process. In order to test our hypotheses we performed a number of statistical analyses on a unique hand‐collected dataset including IIRC and non‐IIRC Pilot Program companies for the 2012 and 2013 fiscal years. Our results indicate that industry and some firm‐level characteristics (board size and diversity) do play a significant role in the determination of materiality disclosure, whereas the legal environment in which companies operate does not. Also, we found that IIRC Pilot Program companies disclosed more information about materiality than their competitors that did not join the program. This paper provides interesting insights for policy makers (in particular, the IIRC) and extends previous academic literature on integrated reporting. Copyright © 2016 John Wiley & Sons, Ltd and ERP Environment