The first civil charges will be forthcoming "very soon" in the stock options timing scandal involving dozens of U.S. companies, the nation's top securities regulator said Monday.

Asked about the scandal after a meeting, Securities and Exchange Commission Chairman Christopher Cox told reporters, "I can only speak to the civil charges for which we are responsible, but I think, very soon."

The SEC, FBI and federal prosecutors are investigating nearly 60 companies to determine if they have manipulated the grant dates and exercise prices of stock options to boost the profits attainable by the corporate executives who got them.

"Each day, of course, we learn more," Cox told reporters. "But for some time now it's been abundantly clear that these were not episodic instances. But rather there were widespread problems, certainly during the 1990s."

Two finance professors who were behind some of the research that has led to regulatory probes made public a new study Saturday that showed almost 30 percent of companies in the past decade manipulated stock option grants to top executives at some point.

Cox has said the investor protection agency will offer guidance to corporate America within weeks on how to handle stock options as part of a broader set of rules aimed at improving the disclosure of executive pay.

Companies targeted in the investigation range from health care services company UnitedHealth Group Inc. (UNH), which has warned of a possible $286 million profit restatement, to several high-tech concerns in Silicon Valley.