Preet Bharara, the United States attorney who successfully prosecuted Raj Rajaratnam and dozens of other insider traders, has lashed out at a corporate culture that encourages walking the line between legal and illegal activity.
Warning Wall St that none of its largest firms or most powerful individuals were "too big to prosecute", Bharara said financial market players too often calculated it was worth taking the risk of a fine rather than ensuring they played clearly by the rules.
There appears, he said, a culture of "minimalism, of doing the minimum rather than staying comfortably clear of the line".
"We keep witnessing successful and monied individuals putting their companies and liberty at risk. It begs the question, is corporate culture becoming increasingly corrupt? Is ethical bankruptcy on the rise?"
Bharara, US Attorney since 2009, has emerged as a powerful force for change on Wall St as he and his staff have aggressively pursued wrongdoing.
They have used wiretaps to outwit traders and executives who carefully restrict the material they commit to paper or to email, and secured guilty verdicts or pleas in three dozen out of 49 prosecutions for insider trading, plus began the first charges for reckless lending in the lead-up to the credit crisis, against Deutsche Bank.
"Our job is to increase the cost and risk of engaging in illicit conduct," Bharara said.
"Anyone who engages in insider trading is especially foolish or pathological, and certainly doesn't belong in any field where rational risk assessment is part of the job description."
Indian-born Bharara came to national prominence as chief counsel to the New York Senator Chuck Schumer when the Senate judicial committee was investigating the politicisation of appointments in the Justice Department.
As US Attorney in the Southern District of New York, which covers Wall St, he heads the office that launched the political careers of Eliot Spitzer and Rudy Giuliani.
Bharara said there will always be rotten apples "but apples are more likely to rot in certain climates".
Bharara recounts the reaction he receives to his speeches at business schools. After describing the perils of walking close to the line, a student will inevitably ask: how close to the line is the right distance? "I'm tempted to say, 3 feet. I disagree with the premise of the question."
Rajaratnam was convicted last month on 14 counts of fraud and conspiracy. Galleon Group, his hedge fund, was once one of the most powerful on Wall St, but some of its trades were based on illegal tips from a network of corporate insiders.
Two other insider trading trials are under way, of Winifred Jiau, an executive from an "expert network" firm which brings together corporate executives and hedge fund traders, and the senior Galleon trader Zvi Goffer.