Quality issues of implied volatilities of index and stockoptions in the OptionMetrics IvyDB database

Abstract For stock and index options in the United States, OptionMetrics records prices at 3:59 p.m., not 4:00 p.m. as assumed in previous literature. The resulting 1‐min time discrepancy with closing share prices creates artificial variability in implied volatility spreads and strongly affects market‐wide spreads.