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 success as an investor means that the portfolio of stocks within Berkshire Hathaway get a lot of attention. Although you always have to make your own buy-and-sell calls, there are a couple of interesting stocks inside Buffett's investment vehicle worth thinking about today.

When I make reference to Buffett's favorite stock, I'm talking about none other than Berkshire Hathaway itself. Buffett has authorized the repurchase of $77.8 billion worth of Berkshire stock since 2018, which is more than twice the amount the conglomerate invested in Apple.

Investors can often benefit from following the recent movements and decisions made by the biggest names in the market, especially if they can work through reverse engineering some of the reasoning behind these decisions.

Diversification ranks among the most important components of many investment strategies. However, one of the world's greatest investors isn't gung ho about the idea. Warren Buffett once said, "Diversification is protection against ignorance.