Following the investing strategy of legendary investor Warren Buffett hasn't been a bad idea for investors. The CEO of Berkshire Hathaway (BRK.A 0.21%) (BRK.B 0.12%) has a history of picking great companies and owning their shares for a long, long time. That's usually panned out quite well for Buffett and Berkshire shareholders.

However, even though Buffett's favorite holding period might be forever, he sometimes decides it's time to pull the plug on a long-held stock. When Berkshire reported its latest quarterly portfolio moves, one of Buffett's oldest holdings got the unceremonious boot. Moreover, another longtime stalwart in the Berkshire portfolio could be right on its tail in the months to come. Below, we'll look at all five holdings and what Buffett did late in 2020 to change things up.

No change in several of Buffett's oldest holdings

The stock that's been in the Berkshire portfolio the longest is Coca-Cola (KO 0.52%). Buffett made a 400 million share purchase, adjusted for subsequent stock splits, way back in 1988. That holding has stayed untouched for the past 33 years, and consistent dividend growth has given Buffett rising rewards for his continuous holding.

With Coca-Cola paying $1.64 per share in total dividends over the past year, Berkshire got $656 million in dividend income in 2020 -- a reasonable return on a holding worth about $20 billion that ranks among the three largest positions in the portfolio. It also represents a 9% stake in Coca-Cola.

Nothing changed in the position in the most recent report from Berkshire. As long as there's a can of Diet Coke on the table in front of Buffett at Berkshire's annual shareholder meeting, there probably won't be any sales of its Coca-Cola stock holding in the future.

American Express (AXP -0.14%) is another early pick of Buffett's and has been a presence in the portfolio since 1993. The Berkshire position has stayed constant at around 151.6 million shares for years and is currently vying for position with Coca-Cola at just under the $20 billion mark.

American Express' 1.3% dividend yield isn't as lucrative as the soft-drink giant's, but AmEx stock has delivered more growth in its share price. Buffett left his nearly 19% stake in American Express unchanged to finish 2020, and it's likely he'll stand pat for the foreseeable future.

Lastly, Moody's (MCO 1.35%) has been among Buffett's picks for more than two decades. Unlike AmEx and Coca-Cola, Berkshire has sold off substantial portions of its Moody's holdings in the past, most notably during the aftermath of the financial crisis in 2009.

Nevertheless, Buffett has liked the ratings agency's business enough to retain a 13% stake worth about $7 billion at recent prices. Barring another controversy of a type similar to what prompted the initial sale, it seems likely that Moody's will keep a presence in the portfolio.

Bank vault in silver, with ramp up to the inner room.

Image source: Getty Images.

One bank gets shown the door -- and another might follow

Buffett did make two changes that affected the other pair of his five longest-held stocks. M&T Bank (MTB 1.32%) has been part of Buffett's holdings since he made a preferred-stock investment in the early 1990s. However, M&T has been one of the many banks that Berkshire gradually reduced beginning in early 2020. In the end, it took only three quarters for the bank to get completely eliminated from Buffett's holdings.

In addition, Wells Fargo (WFC 1.66%) continued to see a big decline in the size of its position within the Berkshire portfolio. With a history dating back to 1989, Wells, at times, had more than 10% of its outstanding shares in Buffett's hands, with a position topping out at almost 480 million shares. In the past year, that stake has shrunk from 323 million shares at the beginning of 2020 to just 52.4 million at year-end.

The $1.6 billion value of that stake now represents less than 1.3% of Wells Fargo's outstanding shares. Given the consistent reduction, it seems almost certain that Wells Fargo will fade into the sunset sometime in 2021 -- and many will say good riddance, given the bank's persistent controversies over the years.

Changing of the guard?

Some investors are concluding that the sale of long-held stocks at Berkshire means that Buffett is no longer really managing the company's portfolio. Indeed, the CEO does have heirs apparent in the wings, ready and willing to take over when necessary.

Most Berkshire shareholders, however, want Buffett in charge as long as possible. That might mean substituting better choices for long-held stocks in the portfolio, but that's not a problem if it means holding the most suitable investments to produce big gains in the long run.