I thought that was a strange takeaway for the article to take. His analysis was correct. He was undone by a factor he didn't even contemplate. His confidence

I thought that was a strange takeaway for the article to take. His analysis was correct. He was undone by a factor he didn't even contemplate. His confidence in his "analysis" was spot on. There's definitely a lesson here, but I would not call it over-confidence. If the bank had gone under, would that have been called over-confidence on the part of his friend? At some point, every mistake of any kind whatsoever is called "over-confidence".