The defense punched back that the government had no direct evidence.
Gupta, 63, once a boldface name in business and charity circles, is the most prominent corporate executive charged in a U.S. government crackdown on insider trading in recent years. Galleon Group founder Rajaratnam, an erstwhile friend and business associate of Gupta, was convicted of insider trading a year ago and is serving an 11-year prison term.
Gesturing with his left arm toward Gupta in a Manhattan federal courtroom, prosecutor Reed Brodsky said the case "is about this man" and "how he violated his duties and abused his position as a corporate insider."
As Brodksy delivered his opening argument to the jury, Gupta stared at him, barely moving in his seat at the defense table. His wife, Anita, and their four adult daughters sat in the front row, also absorbed by the proceedings.
During his turn at the podium, Gupta's lawyer Gary Naftalis painted a very different picture of Gupta, who was born in India and attended Harvard Business School before heading to McKinsey & Co management consultancy.
Naftalis repeatedly told the jury that there was "no real, hard, direct evidence" against him despite 10 months of FBI wiretaps on Rajaratnam's phones in 2008 and 2009.
"Rajaratnam had sources all over town giving him information. He even had sources at Goldman Sachs," Naftalis told the 12-member jury, which includes a nurse, an elementary teacher, and two executives.
The trial is expected to last three to four weeks. The government will call its first witnesses on Tuesday.
One of the legal challenges for prosecutors in the trial is to prove beyond a reasonable doubt that Gupta was Rajaratnam's source for a host of secrets while serving on the boards of Goldman Sachs and Procter & Gamble <PG.N> between March 2007 and January 2009. They also have to prove Gupta benefited.
Naftalis argued in his 45-minute opening statement that Gupta had no reason to illegally spill corporate secrets to Rajaratnam, someone "he felt lost him a lot of money and betrayed him." The men had a falling out in 2008 and Gupta lost all $10 million of an investment with Galleon funds.
Assistant U.S. Attorney Brodsky told the jury that Gupta and Rajaratnam were invested together in a fund called Voyager Capital Partners for several years. He said while they went their separate ways "that doesn't undo what happened."
Gupta faces a possible maximum prison term of 25 years if he is convicted on the charges of securities fraud and conspiracy.
Goldman will play a key role at the trial. One of the government's core allegations is that Gupta tipped Rajaratnam to a $5 billion investment by Warren Buffett's Berkshire Hathaway Inc in Goldman during the 2008 financial crisis and Goldman's surprise fourth-quarter loss that year.
Brodsky told the jury it would hear evidence that on September 23, 2008, Gupta called Rajaratnam 16 seconds after a special Goldman board meeting approved the $5 billion investment.
Rajaratnam then ordered his traders to buy Goldman stock, prosecutors contend. The investment boost to Goldman was not made public or known to ordinary investors until after the market closed that day, Brodsky said.
"It was against the rules for Gupta or anyone else who knew to tell anyone else about it," Brodsky said in his statement.
Goldman has not been charged with any wrongdoing.
Before the jury was seated, Brodsky told Judge Jed Rakoff that the government plans to call former Goldman banker Byron Trott, a long-time Buffett confidant, and William George, a director at the investment bank since 2002, as witnesses this week.
Other witnesses who could take the stand during the trial include Goldman Chief Executive Lloyd Blankfein, who testified for the government at the Rajaratnam trial and said Gupta breached his fiduciary duty to the investment bank.
The case is USA v. Gupta, U.S. District Court for the Southern District of New York, No. 11-907.