Large U.S. companies rarely mention the effect of a leap day in financial reports; only 12 companies in the S&P 500 did so in 2020, said Matthew Glendening, associate accounting professor at the University of Missouri, citing disclosure rates based on Calcbench data. “While materiality thresholds are often left to managers’ discretion, disclosure would be more warranted for firms with such greater percentages for the effect of leap-day sales on year-over-year quarterly sales increases for the quarter,” Glendening said.

https://www.wsj.com/articles/what-companies-need-to-know-when-accounting-for-leap-day-a14374f1?ref=thediff.co