The Great Danger in Derivatives

Nebraska has prided itself on public power it was originated back I believe in the 30s when George Norris was a very powerful senator here. It's been a source of pride but lately it's been aSource of cost too okay shareholder sections three Good morning mr. Buffett and mr. Munger my name is Adam Bergman I'm with Sterling Capital in Virginia Virginia Beach in your 2008 shareholder letter you said derivatives are dangerous they have made it almost impossible for investors to understand and analyze our largest commercial banks and investment banks. How do you analyze and value companies like Bank of America Merrill Lynch and other commercial banks that Berkshire has investments in relative to their significant derivative exposures thanks yeah derivatives do