The backdating probes are clearly having an impact on performance.

Concerned that allegations of executives living it up after backdating options points to another Tyco, Adelphia or WorldCom, panicked investors are selling out, reports the Los Angeles Times.

No charges have been filed and we are still to find out whether the backdating is illegal, but a NASDAQ index of 575 computer related shares is down 9.3 per cent to date.

Silicon Valley and stock options go together like a jigsaw, something I blogged on last week.

The backdating issue was first exposed by Norwegian academic Erik Lie who reckons he is no whistleblower.

"A whistleblower is someone on the inside of a company who reveals wrongdoing. I see myself as a researcher - I have looked at the data and identified trends. That is what researchers do. This is my 15 minutes of fame. I have no doubt that my 15 minutes will pass," he told The Guardian.

But departing SEC commissioner Cynthia Glassman saying some of the backdating has been "clearly illegal". You can can hear her talk about it here.

If she's right, then the stink over backdating will be around for a lot longer than 15 minutes.