They are under birkshire But buffet made the vast majority of his wealth though the 50% aquisition of Birkshire in the 60's at $8 a share. He also made a lot of monny by buying coke cola in the early 80's but his current recommendations are bloated stocks not poised for much more growth and have underperformed. He didn't get rich by just buying and selling stocks as most people are mistaken to believe.