Now a little more than a week into Rajat Gupta's insider trading trial, things are really starting to percolate.

Gupta, the former director of Procter & Gamble Co. (P&G) and Goldman Sachs Group Inc. and the centerpiece of the U.S. government's recent efforts to curb insider trading, is accused of passing tips to former hedge fund manager Raj Rajaratnam.

Arrested last October, Gupta has pleaded not guilty and asserts that the government's evidence is circumstantial.