Lloyd Blankfein, chief executive of Goldman Sachs Group, told jurors at the insider-trading trial of one of the investment bank’s former directors that “all parts” of a 2008 board meeting that the two attended were confidential.

“If something is discussed in a board meeting, it is confidential,” Blankfein said, when asked about a June 2008 board meeting in St. Petersburg, Russia, that he and defendant Rajat Gupta both attended. “All parts of it were confidential.”

Blankfein took the stand at the Manhattan federal court trial of Gupta, the second time in 14 months that the Goldman leader has been a star government witness at a major insider-trading trial. Last year, Blankfein testified at the trial of Raj Rajaratnam, the now-imprisoned hedge-fund manager whom Gupta is accused of tipping with some of Goldman’s most guarded secrets.

The June 2008 board meeting is not directly connected to any of the charges in the case, but an FBI wiretap of Rajaratnam’s phone begins with Rajaratnam telling Gupta he heard a rumor that “Goldman might look to buy a commercial bank.” Gupta’s response is that “this was a big discussion at the board meeting.”

Goldman did not acquire any bank. The two also discussed another board meeting topic: whether Goldman should consider acquiring insurance giant American International Group. Rajaratnam did not trade on the speculation, and Goldman did not buy AIG.

Blankfein and Gupta did not look at each other as Blankfein entered the courtroom, but as he left the witness stand during a jury break, Blankfein raised his head and eyebrows in acknowledgment of Gupta, who stood at the defense table. Gupta’s tense expression did not change, but his gaze followed Blankfein.

U.S. prosecutors called Blankfein to underline evidence of corporate confidentiality and fiduciary duties that the jurors have already heard several times since the trial began May 21.

Assistant U.S. Attorney Reed Brodsky asked Blankfein to read parts of Goldman’s confidentiality and ethics policies. He was also guided through rules for the board of directors and boardroom meeting minutes in 2007 and 2008 to set the stage for events at Goldman tied to the insider-trading charges against Gupta.

“At this time, there were a lot of economic events, a lot of external events, affecting the fortunes of the firm,” Blankfein testified.

Tuesday is a free day for the trial. Blankfein’s testimony will resume Wednesday or Thursday.

Prosecutors contend that Gupta, 63, passed inside tips to Rajaratnam about the bank’s financial results in 2007 and a $5 billion investment in Goldman from billionaire Warren Buffett at the height of the financial crisis in September 2008.

Rajaratnam was convicted of 14 insider-trading counts last year and he is serving an 11-year prison term. If convicted, Gupta also faces years in prison.

Gupta, a retired former global head of the McKinsey & Co consulting firm, has pleaded not guilty. Gupta’s lawyers say their client had nothing to gain financially by giving inside stock tips to Rajaratnam, the founder of the Galleon Group hedge fund. Gupta and Rajaratnam were friends and business associates.

Goldman has not been accused of wrongdoing.

According to the indictment, Gupta told Rajaratnam about Goldman’s first-quarter 2007 earnings the day before the information was made public. Gupta also is accused of tipping the hedge-fund manager seconds after the Goldman board approved a $5 billion investment by Buffett’s Berkshire Hathaway on Sept. 23, 2008.

— Reuters

: Rajat Gupta charged with insider trading: The former Goldman Sachs director turned himself in to authorities Oct. 26.

: Leaders of the banking industry: These executives head some of the nation's largest and most closely watched financial institutions.