Black-Scholes works for short-term options, but if it's a long-term option and you think you know something [about the underlying asset], it's insane to use Black-Scholes.

Once you get into debt, it’s hell to get out. Don’t let credit card debt carry over. You can’t get ahead paying eighteen percent.

It's dishonourable to stay stupider than you need to be

Derivative trading with mark-to-market accounting degenerates into mark-to-model. Two firms make a big derivative trade and the accountants on both sides show a large profit from the same trade.

One of the smartest things a person can do is dampen investment expectations, especially with Berkshire. That would be mature and responsible. I like our model and we should do nicely

If you have competence, you know the edge. It wouldnt be a competence if you didnt know where the boundaries lie. Asking whether youve passed the boundary is a question that almost answers itself.

I'm proud to be associated with the value system at Berkshire Hathaway; I think you'll make more money in the end with good ethics than bad.