Warren Buffett is a big fan of portfolio concentration and placing large wagers on his best ideas. Kicking off 2025, roughly 80% ($238 billion) of the $297 billion portfolio Buffett is overseeing at Berkshire is invested in just nine unstoppable stocks.

Warren Buffett's Berkshire Hathaway owns one of the world's most closely watched stock portfolios. It holds stakes in 46 stocks and exchange-traded funds that are worth $296.8 billion, or 30% of its entire market capitalization.

The Berkshire Hathaway chief sticks to a winning investing formula, but he does not sit still.