Abstract
We examine the factors underlying the presence of earnings announcement premia. We find that
the premia persist beyond the sample period examined in prior studies (ending in 1988), although
they decline in magnitude after 1988. Further, premia are lower on the expected than the actual
earnings announcement dates. We document that increases in voluntary disclosures result in lower
premia, despite the increase in return volatility over time. Finally, our evidence suggests that the
premia are not completely eliminated because of the costs of arbitrage.
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2007 Elsevier B.V. All rights reserved.