A guy worked at the same firm as his wife who was a senior on an audit of a business got word from her that it was distressed (this information was not to be released public for months.) Everyone on the audit knew they were fucked, but it is very illegal to discuss this with outside parties. So the husband was drunk at a bar, and an old friend from highschool came in and asked him if he knew anything about the business. He said, "Hell yea, that stock isn't worth a nickel. They're going to be bankrupt in a year (the stock was then trading for $3.00 a share.) Immediately after that, the guy called his father who told his broker "I've got some information from a guy on the audit team of (x business), sell everything I have." Well, needless to say, this got to the SEC and the company, and my Professor (who was the manager of the audit) got a call from a managing partner located across the U.S. at their firm HQ. "You and your team don't go anywhere, we have a problem, and we're sending our legal counsel."

By the next day, that guy that uttered that little tip at the bar was unemployed, and there were pending civil and criminal cases against him. When you give a tip like that, you can literally cost your firm HUNDREDS OF MILLIONS OF DOLLARS. .