Robert Moffat, a former senior International Business Machines Corp executive who pleaded guilty in the closely-watched Galleon hedge fund insider trading probe, was sentenced Monday to six months in prison and a $50,000 fine.

U.S. District Judge Deborah Batts imposed sentence on Moffat, whose more than three-decade long career at IBM was left in ruins after he was arrested and charged in October of2009 for what prosecutors said was a minor role in the purported scheme.

Moffat, once considered a candidate to become IBM's chief executive, became embroiled in the insider trading probe during an extra-marital affair with a trader, Danielle Chiesi.

She has pleaded not guilty to charges related to insider trading and is scheduled to stand trial with Galleon founder Raj Rajaratnam in January.

Rajaratnam has also pleaded not guilty in a case U.S. prosecutors describe as the biggest probe of insider trading at hedge funds in the United States.

The case is USA v Moffat, U.S. District Court for the Southern District of New York, No. 10-00270.