The first high-flying AI stock Warren Buffett secretly owns is industry-leading networking-solutions provider Broadcom (NASDAQ: AVGO). New England Asset Management closed out the third quarter with 19,855 shares of Broadcom, which has a present-day value of nearly $4.5 million.

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.

The Oracle of Omaha has more than enough justification to add to the roughly $78 billion he's spent buying shares of his favorite stock since mid-July 2018.

Berkshire Hathaway CEO Warren Buffett was born in Omaha, Nebraska, in 1930 and is one of history's most successful investors. Trained under the tutelage of Benjamin Graham, the father of value investing,

Warren Buffett is widely considered one of the greatest investors ever because he has delivered excellent returns for a long time. The Oracle of Omaha's investing strategy was effective 10 years ago.