One consequence of the shift to fair value measurement is the emergence of voluntary
disclosures in audited financial statements that question the reliability of mandated fair
value information. We refer to these disclosures as reliability disavowals. We examine
stock option volatility estimates disclosed under SFAS 123 and test whether disavowals
are informative (opportunistic) by examining whether ex ante firm characteristics,
forecast bias, and prediction difficulty are consistent with informative (opportunistic)
disclosure. Our results support the hypothesis that disavowals inform users about
the reliability of volatility estimates, but there is also limited evidence consistent with
managers using disavowals opportunistically