Here’s some fresh fodder for armchair ethicists to chew on: Should you help a friend who has been convicted of a crime, when that friendship and business interests overlap?

Earlier this week I spent a few hours at the federal courthouse in downtown Manhattan reading through the hundreds of letters sent on Rajat Gupta’s behalf to U.S. District Judge Jed Rakoff. Gupta is the former Goldman Sachs board member and McKinsey & Co. managing partner who is scheduled to be sentenced for securities fraud next week. Prosecutors have said they believe Gupta should receive about eight to 10 years in prison.

The letters that most interested me were from people with ties to Berkshire Hathaway, the conglomerate run by Warren Buffett. One person who wrote was Microsoft founder Bill Gates, who is a member of Berkshire’s board of directors. Another was Ajit Jain, Berkshire’s reinsurance chief. A third was Manoj Singh, chief operating officer of Deloitte Touche Tohmatsu. Deloitte’s U.S. arm, Deloitte & Touche LLP, is Berkshire’s independent audit firm.

Here’s the rub. Gupta was convicted of illegally tipping his friend and business partner, hedge-fund manager Raj Rajaratnam, about Berkshire’s $5 billion investment in Goldman in September 2008. Rajaratnam, who got an 11-year prison sentence, used that information to trade illegally in Goldman’s stock. This is why it seems awkward, and perhaps even inappropriate, for Gates, Jain and Singh to have written to the judge seeking leniency for Gupta.

Their letters were of a personal nature. None identified his business relationship with Berkshire. Nonetheless, it would have been better for the three of them to have kept their views to themselves on this occasion.

When Gupta passed along the illicit tip, he wasn’t only misappropriating information from Goldman. He was stealing from Berkshire, too. By sending their own personal appeals for leniency, Gates, Jain and Singh chose a side and put themselves at odds with those Berkshire stakeholders who disagree with them -- and surely there are plenty who do.

My own view is this isn’t something a corporate director, a high-ranking executive or a professional at an ostensibly independent audit firm should have done. (Singh identified himself in his letter as Deloitte’s chief operating officer.)

One final note: Gupta also was convicted of providing Rajaratnam with inside information he learned as a board member at Procter & Gamble, which is another Deloitte audit client. Ironically, Deloitte’s own former vice chairman, Thomas Flanagan, pleaded guilty to insider trading in August; the government said he made $420,000 of illegal trading profits using inside information he obtained about several Deloitte audit clients. Separately, Flanagan in 2010 settled a complaint by the Securities and Exchange Commission that accused him of violating auditor-independence rules by trading in shares of several Deloitte audit clients -- including Berkshire.

Flanagan is scheduled to be sentenced Oct. 26, two days after Gupta. The docket in Flanagan’s case says the character reference letters written on his behalf have been sealed.

(Jonathan Weil is a Bloomberg View columnist. Follow him on Twitter.)

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