Apple's stock plunge is taking a multi-billion bite out of Berkshire Hathaway's stock portfolio

The drop in Apple’s stock price (AAPL) has hit Warren Buffett’s Berkshire Hathaway’s (BRK-A, BRK-B) stock portfolio.

“As of market close Jan. 7, the value of four of Berkshire's five largest holdings has decreased since Sept. 30,” writes S&P Global’s Jason Woleben on Thursday. “On a cumulative pro forma basis, investments in Apple Inc., Wells Fargo & Co., Bank of America Corp., and American Express Co. are down just over $25 billion during that time, with Apple's 34% drop wiping out $19.2 billion of Berkshire market value.”

As of the third quarter ended September 30, Berkshire Hathaway owned more than 252.47 million shares of the iPhone-maker, making it the No. 1 largest equity holding. Assuming the position is unchanged, it’s valued at over $38.83 billion based on Thursday’s closing price of $153.80. At the end of the third quarter, the position had been valued at over $56.99 billion.

Apple’s stock came under pressure after CEO Tim Cook said the company lowered its revenue guidance for the first fiscal quarter of 2019, citing weakness in China and lower-than-expected iPhone sales.

The 88-year-old has historically shied away from tech investments. The “Oracle of Omaha” has hinted, however, that his investment deputies— Ted Weschler and Todd Combs— were responsible for buying Apple.

Berkshire first invested in Apple during the first quarter of 2016 and continued to add to its position in subsequent quarters. Much of that buying was when Apple’s stock traded the lower $100s. It’s possible Berkshire is still in the money on its position. And any losses are paper losses at this point.

Elsewhere, Berkshire loaded up on financial stocks during the third quarter, including a new positions in JPMorgan Chase (JPM) and PNC Financial (PNC). Buffett boosted bets on Bank of America (BAC), Goldman Sachs (GS), Bank of New York Mellon (BK).

Financials have come under pressure since the third quarter, with Goldman Sachs dropping 21% in that timeframe.

Berkshire has a couple hundred billion dollars invested in stocks. Berkshire also operates businesses across a variety of sectors, including railroads, manufacturing, retailing, services, insurance, etc.

For now and for what it’s worth, it doesn’t look to be all bad news for Berkshire during the past three months.

“The lone bright spot, Coca-Cola Co., is up $300 million over that period,” Woleben said.

Berkshire Hathaway will release its stock holdings for the fourth quarter of 2018 in its upcoming 13F filing due in mid-February.

—Julia La Roche is a finance reporter at Yahoo Finance. Follow her on Twitter.