Prosecutors allege Gupta had co-conspirators US prosecutors have claimed eight people are co-conspirators in an alleged insider trading scheme involving Rajat Gupta, the former McKinsey director, as his case heads toward trial. Mr Gupta was charged last year with allegedly passing secret corporate information about Goldman Sachs and Procter & Gamble while serving on their corporate boards to his friend and business partner Raj Rajaratnam, the co-founder of Galleon Group. Mr Rajaratnam was convicted of insider trading last year and sentenced to 11 years in prison. Mr Gupta has denied wrongdoing. His case is set to go to trial on May 21. In a court filing, prosecutors identified two of the eight alleged co-conspirators by name. They are Michael Cardillo, a former Galleon trader who pleaded guilty last year and is co-operating with the government, and Ian Horowitz, a former Galleon trader who has not been charged with any wrongdoing. Mr Cardillo admitted to trading shares of JM Smucker in June 2008 before it was publicly known that the maker of jams was acquiring Folgers from Procter & Gamble. He also traded in Procter & Gamble shares before the company announced quarterly earnings in 2009. Mr Gupta has been charged with passing the same earnings and takeover information to Mr Rajaratnam, according to an indictment. Mr Horowitz's name surfaced during Mr Rajaratnam's trial when Adam Smith, a Galleon portfolio manager who pleaded guilty, admitted he tried to persuade Mr Horowitz to confess to insider trading during a recorded call he made at the direction of the Federal Bureau of Investigation. Lawyers for Mr Gupta previously expressed an interest in interviewing him, which the judge overseeing the case granted their request. It is not clear whether the alleged co-conspirators will testify in the government's case. Defence lawyers saw a preview of some of the government's evidence of tips involving Goldman Sachs during Mr Rajaratnam's trial. In a ruling last year in the Securities and Exchange Commission's civil lawsuit against Mr Gupta, the judge said defence lawyers could depose several people ahead of the criminal trial, including Lloyd Blankfein, chief executive of Goldman Sachs, and from Galleon, Mr Horowitz, Ananth Muniyappa, Gary Rosenbach, Leon Shaulov, and Brock Vandervliet. He denied the defence request to interview Mr Cardillo and David Loeb, a Goldman salesman who a person familiar with the matter said is also under investigation. Mr Loeb has not been accused of wrongdoing. Lawyers for Mr Gupta deposed Mr Blankfein in February. On Tuesday, the judge said they were entitled to interview him again to learn about any advance preparation he had with government lawyers. The SEC was also ordered to turn over any exculpatory materials they have from interviews with 44 individuals.