American Technology Research analyst Shaw Wu thinks it's a "positive" that Apple has now revealed the findings of its stock options investigation.

He sees the company as having taken some significant steps forward to resolving the situation.

However, the Wall Street Journal reported on Thursday that federal prosecutors have begun to investigate Apple, and that Apple lawyers met with prosecutors and securities regulators earlier this week.

Wu notes Apple CEO Steve Jobs' admission that he was aware of "a few" of the favourable stock option grants, but adds: "In the worst case scenario where Apple is guilty of improper options grants, we do not believe Jobs is liable."

This is because stock options grants are handled by an independent committee at Apple, he notes.

At issue are 15 instances in which grants made as part of the compensation package to some Apple employees have grant dates that preceded the approval of those grants.

This is a practice in which stock options are retrospectively dated back to a time at which stock was weak, effectively guaranteeing profit. While this isn't illegal in the US, companies are expected to disclose that this has taken place at the time.

Apple's investigation found the most recent such grant was made in January 2002. The company will be forced to restate its earnings to take the debacle into account.

In a note to clients, Wu speculates as to the identity of the two former officers of the company Apple mentioned as causing "serious concerns" in its investigation into stock option fixing.

He warns these former officers could be the highly respected former chief financial officer Fred Anderson, and former general counsel Nancy Heinen.

Anderson resigned from Apple's board this week, while Heinen quit late last year, and reportedly hired lawyers to represent her while Apple's internal probe into the affair took place.

Anderson was instrumental in bringing Jobs back to Apple in the '90s. He's also a co-founder (with U2 singer, Bono, and Roger McNamee) of venture capital firm Elevation Partners.

McNamee told the Financial Times: "I have known Fred as a friend and a business associate for many years. During this time, I have been impressed with his thoroughness, his uncompromising character and the high professional standards to which he has held himself."

Despite Apple's current troubles, Wu reflects the view of the majority of Wall Street investors, who he advises should maintain their investment in Apple with a $91 target price.