Buffett invested in Heinz in 2013 and two years later, Heinz merged with Kraft Foods. He bought 326 million shares during this merger at a cost of around $24.6 billion. He has held on to that stake, which is now worth $11.4 billion.

Some of the Oracle of Omaha's most-popular buys -- as well as Berkshire's largest holding -- offer robust upside potential in 2025.

Berkshire sold 20.7 million of those shares in the third quarter of 2024, but its 86.4 million remaining shares are still worth $949 million and give it a 1.8% stake in the company. Berkshire's stake in Nu only accounts for 0.3% of its entire portfolio, but the Latin American bank is still growing much faster than its brick-and-mortar competitors.