He was indicted in December 2005 on 42 charges of insider selling.

Even in a slow year for insider selling, some executives did well.

Such praise may compensate for reports of insider selling and mediocre performance from investments.

During the last six months, insider selling has picked up.

"Contrary to everyone's assumptions, a deleterious effect from insider selling can't be assumed," he said.

Because of these regulations, aggressive insider selling "might even suggest that insiders do not have negative information" about their companies, according to the professors.

That makes investors particularly vulnerable to a downdraft caused by insider selling.

Add in worries over heavy insider selling, and some longtime fans of the company are growing more cautious.

As a result, he concludes, the current high level of insider selling provides no signal for the market's direction.

Only if prices begin to decline from current levels and insider selling continues or accelerates would he recommend getting out of stocks.