When is the best time of day for a company to dump bad news?

Using these new metrics, the authors find that markets really do get distracted sometimes. Not on Fridays, no, but after hours and on busy days when lots of companies are filing at once. They also find that companies change the timing of their quarterly announcements often enough—for innocent reasons—that a devious maneuver won’t call attention to itself. “That frequency of benign changes is the camouflage necessary for strategic changes,” deHaan says. “It means there’s a big enough pool to hide in.”

So it’s not too surprising, then, that companies appear to do just that. The data shows that earnings reported after hours and on busy days—as well as on Fridays, interestingly—are significantly worse (relative to consensus forecasts) than at other times. “Obviously we can’t know what a firm’s intention was in any specific case,” deHaan says, but in aggregate, “it seems that managers do try to hide bad news by announcing it in periods of low attention.”