
Warren Buffett is one of the most successful and popular investors in the world. Whenever he buys or sells stocks, it makes global headlines — and he can’t keep his moves secret for long.
According to Securities and Exchange Commission rules, larger investors like Buffett have to disclose their transactions quarterly by filing Form 13F. In August 2025, Buffett announced that his company, Berkshire Hathaway, had accumulated 5 million shares of UnitedHealth Group (UNH). At current market prices, that stake is worth roughly $1.72 billion.