Warren Buffett's Berkshire Hathaway (BRK.A -0.56%) (BRK.B -0.45%) recently filed its 13F form, which shows investors its latest positions. And by comparing them to previous filings, investors can see which stocks the company has been buying and selling. Investors often pile into stocks that Berkshire has been buying, wanting to mimic the company's moves.

Here were the five biggest moves that Berkshire made last quarter (which covered the last three months of 2024), based on changes in share count.

Bank of America: 117 million shares sold

Buffett has long been a fan of bank stocks, and it's typically not hard to find them in Berkshire's portfolio. One of his largest holdings is in Bank of America (BAC 0.48%). It's the second-largest bank in the U.S. based on its assets, and investing in it is a great way to profit from the country's long-term growth and success. Buffett often encourages investors to "bet on America."

But last quarter, Berkshire unloaded more than 117 million shares of Bank of America stock. Berkshire still has a roughly 9% stake in the top bank and it remains its third-largest holding, behind Apple and American Express. However, the reduction is the most notable move for Buffett this past quarter.

It may not have been specifically due to Buffett's outlook for the particular stock and instead it may have been due to a desire to trim Berkshire's exposure to the sector as a whole, as this isn't the only bank stock on this list.

Nu Holdings: 46 million shares sold

The next-largest move (based on share count) for Berkshire was the reduction of more than 46 million shares of Nu Holdings (NU 1.50%), which provides digital banking services. It has 114 million customers in multiple markets, including Mexico, Brazil, and Colombia. It is a fast-growing business, reporting 58% revenue growth in 2024.

After the stock sale, Berkshire still has more than 40 million shares of Nu Holdings, but in terms of overall value, it's one of its smallest positions, accounting for just 0.1% of the overall portfolio.

Citigroup: 41 million shares sold

Citigroup (C -0.17%) is yet another bank stock that Berkshire trimmed its position in last quarter. The top bank has been involved in restructuring efforts in recent years in order to improve its financial performance, and this year it has continued to cut jobs.

Buffett's sales of Citigroup may be a sign that he isn't optimistic about its turnaround, or perhaps is simply part of a broader goal in reducing his overall exposure to bank stocks. After the stock sale, Berkshire now has less than 15 million shares in Citigroup, making this one of the more drastic reductions his company made during the past quarter. Citigroup currently accounts for 0.4% of Berkshire's overall portfolio.

Sirius: 12 million shares added

Sirius XM (SIRI 6.23%) is one stock that Buffett remains fairly bullish on, and it was a position that saw the largest increase for Berkshire last quarter, as its share count rose by more than 12 million.

The broadcasting company generates money from subscriptions to its satellite radio. With little competition, it has a strong moat, which likely appeals to Buffett. It has also consistently reported an operating profit in each of the past four quarters. It makes up 1% of Berkshire's overall portfolio, and with its recent share purchase, Berkshire now owns a 35% stake in Sirius.

Occidental Petroleum: 9 million shares added

Another big position that Berkshire has is in oil and gas producer Occidental Petroleum (OXY 3.35%). It added nearly 9 million shares to its position in this stock last quarter, and it now accounts for more than 4% of its total portfolio -- making it the sixth-largest holding for Berkshire.

As with Sirius, Occidental is a stock that Buffett clearly likes, as Berkshire has a 28% overall stake in the business. Occidental has generated solid profit margins of around 9% in the trailing 12 months, and with the stock declining by more than 21% over the last six months of the year, Buffett may have been eager to buy on the dip.

Is Buffett bearish on the market?

Investors may be concerned that Buffett is doing a lot more selling than buying of late, and that Berkshire's cash balance continues to rise. It reached a record $334.2 billion as of the end of 2024, which is up from $325.2 billion a quarter earlier.

Buffett may be shifting positions around but Berkshire's portfolio is still worth around $290 billion. While the current economic conditions may be unsettling and worrisome for investors, Buffett has remained invested amid even greater uncertainty in the past, staying the course for decades. Although he may make adjustments to Berkshire's holdings, it's by no means a sign that he's worried about a market crash being around the corner.

He's still invested in the market, and that has proven to be an excellent move over the long haul. Investors may want to also consider changing up the stocks they hold, but it's generally a good move to remain invested in the market rather than being out of it and trying to time it.