Warren Buffett is a famous billionaire investor, and his trillion-dollar conglomerate, Berkshire Hathaway (NYSE: BRK.A)(NYSE: BRK.B), owns nearly 50 stocks in its portfolio. Several of these stocks are in the financial and energy sectors.

Warren Buffett has generated tremendous gains for the long-term shareholders of Berkshire Hathaway over the years. The Berkshire Hathaway portfolio today features stakes in more than three dozen companies that were either selected by Buffett himself or one of his investing deputies.

Buffett has said he made a mistake not buying Amazon stock, but it still took his portfolio managers to press the button. Amazon has incredible opportunities in AI, e-commerce, and more. Amazon stock trades at an attractive valuation.