Warren Buffett has grown Berkshire Hathaway's Apple stake to 50% of its entire equity portfolio and nearly a quarter of its $649 billion market cap

• Berkshire Hathaway's Apple holdings of 887 million shares swelled to a value of $159 billion on Friday.
• That makes the stake worth half of Berkshire's entire equity portfolio, and almost 25% of its $649 billion market capitalization.
• Warren Buffett started to build Berkshire's position in Apple in 2016 and added to it up until mid-2018.

Warren Buffett is known for concentrating his investments to build generational wealth, and Berkshire Hathaway's stake in Apple is no better example of that investment practice.

Berkshire's 887.1 million shares in the iPhone maker swelled to a record value of $159 billion on Friday, a 342% increase from its original cost basis of about $36 billion. That means Apple is now worth more than half of Berkshire's $293 billion equity portfolio, based on data from its third-quarter 13F filing.

And assuming Berkshire hasn't trimmed its Apple position since September 30, the equity stake now represents about a quarter of Berkshire Hathaway's $649 billion market capitalization.

What also makes Buffett's concentration in Apple notable is that it didn't take decades to compound like most successful investments managed by Buffett. Instead, it's only been five years since Berkshire began to build its stake in Apple.

The conglomerate first purchased Apple shares in 2016 and continued buying them until mid-2018, when the position topped 1 billion shares after adjusting for a 4-for-1 stock split in 2020. Buffett has trimmed Berkshire's position in Apple by about 12% since initially building the stake.

Barring any changes since the most recent 13F filing, Berkshire's stock portfolio would be up 13.9% quarter-to-date, according to an analysis by Bespoke. Much of that gain has been driven by Apple's quarter-to-date gain of more than 20%.

Year-to-date, Apple is up 31%, compared to Berkshire Hathaway's return of 26%. Apple's stock price was less than $1.00 away from hitting a $3 trillion valuation on Monday.

Berkshire's three largest positions after Apple are Bank of America, American Express, and Coca-Cola, which make up a combined 30% of the equity portfolio's value. And Berkshire is still sitting on about $150 billion in cash that it has yet to put to work.