This study examines how key market participantsmanagers and analystsresponded to SFAS 123Rs controversial requirement that firms recognize stock-based compensation expense. Despite mandated recognition of the expense, some firms managers exclude it from non-GAAP earnings and some firms analysts exclude it from Street earnings. We find evidence consistent with managers opportunistically excluding the expense to increase earnings, smooth earnings, and meet earnings benchmarks, but no evidence that such exclusion results in an earnings measure that better predicts future firm performance. In contrast, we find that analysts exclude the expense from earnings forecasts when the exclusion increases earnings predictive ability for future performance, but opportunism generally does not incrementally explain exclusions by analysts. Thus, we find that opportunism explains exclusion of the expense from non-GAAP earnings and predictive ability explains exclusion from Street earnings. Our findings suggest the controversy surrounding the recognition of stock-based compensation expense may be attributable to cross-sectional variation in the relevance of the expense for equity valuation, as well as to differing incentives of market participants.