Thus, if backdating explains the stock price pattern around option grants, the price pattern should diminish following the new regulation.
Indeed, we found that the stock price pattern is much weaker since the new reporting regulation took effect.
Unfortunately, these conditions are rarely met, making backdating of grants illegal in most cases.
(In fact, it can be argued that if these conditions hold, there is little reason to backdating options, because the firm can simply grant in-the-money options instead.)David Yermack of NYU was the first researcher to document some peculiar stock price patterns around ESO grants.
Most shareholder approved option plans prohibit in-the-money option grants (and thus, backdating to create in-the-money grants) by requiring that option exercise prices must be no less than the fair market value of the stock on the date when the grant decision is made. For example, because backdating is used to choose a grant date with a lower price than on the actual decision date, the options are effectively in-the-money on the decision date, and the reported earnings should be reduced for the fiscal year of the grant.