The Securities and Exchange Commission is ready to pull the trigger on its first stock-option backdating case, CNBC has learned.

       People at the SEC as well as several defense attorneys representing targets of the wide-ranging probe say that the commission will file its first case within a month. Although there are around 400 cases of backdated stock options that have caught the SEC’s attention, and about 60 under more intense scrutiny, these same people say one case is at the top of the SEC’s list. That case involves Greg Reyes the former high-flying CEO of technology company Brocade Communications.

Reyes resigned from Brocade more than a year ago, after the company announced an earnings restatement stemming from how it accounted for stock options. Since then he has received what’s known as a “Wells Notice” from the SEC, meaning that the commission’s staff is recommending that the agency file civil fraud charges against him over backdating of options. The full-commission must approve the staff’s recommendation before charges are filed, but attorneys working for Reyes believe that a civil case against Reyes is extremely likely given the tenor of some recent meetings with the SEC.

A bigger question is whether Reyes will face a criminal indictment as well. The US Attorney’s office has joined the SEC in a joint investigation of Reyes’ actions, and Reyes’ attorney, according to people with knowledge of the matter, recently met with prosecutors from the US Attorney’s office from the Northern District of California to stave off an indictment of their client.

How did they do? People close to the Reyes defense team say they are cautiously optimistic that the US Attorneys office may back off from brining a criminal case even if the SEC files a civil case against Reyes, as is expected in the coming weeks.

The controversy surrounding backdating of stock options has been at the top of the SEC’s enforcement agenda for more than six months. Stock options are designed to align the compensation of employees with their company’s performance. They give the holder the ability to purchase stock at a strike price at some future date. A lower strike price allows the employee to make more money if and when shares of the company’s stock rise. The strike price is usually set at the date the stock option is granted.

But if an executive can change the date of the strike price - move it back to a day when the shares are actually lower -- the benefits could be tremendous. The SEC and the Justice Department are investigating whether companies and their top executives committed civil and possibly criminal securities fraud by manipulating these dates.

While Reyes’ actions have clearly caught the eye of civil and criminal authorities, his actions also show that many of these cases are far from cut-and-dry. In a recent meeting with officials from the US Attorney’s office, his lawyers made several compelling points. First, that whatever actions Reyes took, he did not do so for self-enrichment, as has been alleged in other cases. They told prosecutors that Reyes’ action benefited company employees, “including low-employees, staff and secretaries,” according to one person with direct knowledge of the meeting. Because of this, they argued, there is scant evidence that Reyes’s actions showed criminal “intent,” a necessary element of any prosecution.

Reyes, they argued had wide discretion to set the date of the option to any point he wanted.