An attorney who worked for indicted Broadcom Corp. co-founder Henry T. Nicholas III has pleaded guilty to evading a banking law and will cooperate with the federal government in a sweeping stock options backdating probe involving his former boss.

Craig Gunther, who oversaw Nicholas' private dealings for more than five years, entered the pleas to two misdemeanor counts Friday and could face up to two years in prison. Under sentencing guidelines outlined in the plea agreement, a sentence of a year or even probation could be imposed.

Nicholas, a billionaire who left Broadcom in 2003, has pleaded not guilty to conspiracy and securities fraud for his alleged role in stock options backdating at the chip maker. He also faces drug charges, including allegations that he slipped Ecstasy into the drinks of business associates.

Nicholas has pleaded not guilty and is free on bail pending trial next year.

Gunther pleaded guilty to evading a banking law that requires that cash transactions of $10,000 or more be reported to tax authorities.

Prosecutors said Nicholas regularly requested tens of thousands of dollars in cash, and Gunther would sign several checks of $9,500 to circumvent the reporting requirement.

Gunther said in a statement released by his attorney that he didn't realize the practice was illegal.