Rajat Gupta's fall from the pinnacle of corporate America arrived in the form of federal securities fraud charges that, when the full arc of the case became clear, constituted one of the most consequential insider trading prosecutions of the post-2008 financial era.

Gupta had been, by virtually any measure, among the most distinguished business figures of his generation: the first non-American managing director of McKinsey & Company, a Harvard Business School graduate whose career had taken him from India to the heights of American corporate governance. He sat on the boards of Goldman Sachs, Procter & Gamble, and American Airlines, among others. His public profile was that of a model immigrant success story and philanthropist.

The government's case alleged that Gupta had passed material non-public information he received as a Goldman board member to hedge fund manager Raj Rajaratnam of Galleon Group — including information about Warren Buffett's $5 billion investment in Goldman during the 2008 financial crisis. Rajaratnam, already convicted in 2011 in what was then the largest insider trading case in US history, had recordings of conversations with Gupta that formed much of the prosecution's evidence.

The case raised questions that went beyond the legal. How widespread were such information flows among the intersecting networks of corporate boards, hedge funds, and advisory relationships that constituted the upper tier of American finance? Were the norms Gupta allegedly violated exceptional or routine? The government's answer — that they were exceptional enough to prosecute — was contested by those who believed the entire system operated on information advantages that only occasional defendants were made to account for.

Gupta was convicted in 2012 and sentenced to two years in prison.