Fund consultants like to require style boxes such as "long-short," "macro," "international equities." At Berkshire our only style box is "smart."

I think once you start putting phony figures into financial statements, you get in a lot of trouble. And we've seen so much of that in the last 20 years.

The dumbest reason in the world to buy a stock is because it's going up.

The most dangerous distractions are the ones you love, but that don’t love you back.

Does the business have a consistent operating history?

Investors should be skeptical of history-based models. Constructed by a nerdy-sounding priesthood using esoteric terms such as beta, gamma, sigma and the like, these models tend to look impressive. Too often, though, investors forget to examine the assumptions behind the models. Beware of geeks bearing formulas.

A pin lies in wait for every bubble and when the two eventually meet, a new wave of investors learns some very old lessons.