To be honest, probably nothing. Rich people are pretty much pros at operating tax shelters, which explains the famous Buffet quote about how he pays a lower tax rate than his secretary.
No, it's better/worse than that. Long-term capital gains (held more than one year) are taxed at 15% for someone like Buffet. He paid a lower rate (17.7% combined short-term and long-term) on taxes than his secretary without trying to avoid taxes.
