* Blankfein, Buffett, Chenault may testify or be mentioned
* US says Gupta leaked Goldman, P&G secrets to Rajaratnam
* Gupta denies charges, trial set to begin on Monday
By Grant McCool and Jonathan Stempel
NEW YORK, May 17 (Reuters) - Lloyd Blankfein, Warren Buffett and other well-known chieftains of corporate America might be called to testify at the insider trading trial starting on Monday of former Goldman Sachs Group Inc and Procter & Gamble Co director Rajat Gupta.
Blankfein, who runs Goldman, and Buffett, who runs Berkshire Hathaway Inc , are among dozens of people that lawyers for the government and for Gupta said on Thursday might be mentioned or might testify at the trial, which is expected to last about three weeks.
Others on proposed witness lists filed on Thursday in the Manhattan federal court are A.G. Lafley, a former P&G chairman and chief executive, and Kenneth Chenault, the chairman and chief executive of American Express Co and a P&G director.
Gupta, the former chief of consulting firm McKinsey & Co, is the most prominent corporate executive charged in a government crackdown on insider trading centered on hedge funds.
He was charged last October with leaking confidential information to his onetime friend, Galleon Group hedge fund founder Raj Rajaratnam, while serving on the Goldman and P&G boards in 2007 and 2008.
Gupta, 63, denies the charges, and has pleaded not guilty to five counts of securities fraud and one count of conspiracy. If convicted, he could face up to 25 years in prison.
His main lawyer, Gary Naftalis argues that the government's case is circumstantial and speculative.
Blankfein testified for the government at last year's high profile trial of Rajaratnam, saying that disclosure of boardroom talks by Gupta violated Goldman's confidentiality policies.
He spoke after jurors heard a wiretapped recording in which Gupta and Rajaratnam discussed Goldman's possibly buying a bank or insurer.
Rajaratnam was convicted and is serving an 11-year prison term, the longest sentence for insider trading in the United States.
Prosecutors have accused Gupta of giving Rajaratnam advance knowledge of Berkshire's $5 billion investment in Goldman at the height of the 2008 financial crisis and Goldman's surprise fourth-quarter loss that year.
They have also accused Gupta of providing non-public information in January 2009 about P&G's quarterly results and in June 2008 about that company's sale of its Folgers coffee unit to J.M. Smucker Co.
MORE THAN 100 NAMES
The defense list names 116 individuals and the government listed 51 people. A small number will actually testify at trial.
Among the other executives named on both lists are David Viniar, Goldman's chief financial officer and Gary Cohn, Goldman's chief operating officer.
Jon Moeller and Mark Belgya, respectively the chief financial officers of P&G and Smucker, are also on both lists. Buffett's name appears only on Gupta's list.
Goldman spokesman Michael DuVally declined to comment. Smucker spokeswoman Maribeth Baertscher said it is cooperating with the government on the Gupta case and that Belgya "has agreed to appear as a witness at the government's request."
P&G spokesman Paul Fox said: "We have been fully cooperating with government investigators on this case, including potentially giving oral evidence if required."
American Express spokeswoman Marina Norville declined to comment. Carrie Kizer, an assistant to Buffett, d id not respond to a request for comment.
The trial begins Monday before U.S. District Judge Jed Rakoff with jury selection and possibly opening arguments. The first government witness could be called on Monday or Tuesday.
Gupta suffered a blow on Wednesday when Rakoff said he intended to let jurors hear four wiretapped conversations, including the conversation between Gupta and Rajaratnam played at last year's trial.
The case is USA v. Gupta, U.S. District Court for the Southern District of New York, No. 11-907.