Former executives at Apple and Broadcom who are embroiled in a stock options scandal could soon face criminal charges. The Wall Street Journal reports this morning that federal prosecutors are also preparing to file charges against former officials at McAfee and KLA-Tencor Corp .

US government investigators are currently examining the backdating of shares at these companies by various company executives.

Over 170 companies in the United States are being investigated by financial authorities after they were alleged to have backdated grant dates to days when share prices were lower, which would potentially have given the perpetrators the chance to make large profits.

This week, two company executives have pleaded guilty to conspiracy and securities fraud in relation to the backdating charges; the ex-general counsel at Monster Worldwide , and the former chief exec of computer game publisher Take-Two .

The firms involved in these scandals have been threatened with delisting by Nasdaq .