OMAHA, Neb. (AP) — Investor Warren Buffett's company has unloaded more of its Bank of America stake, selling nearly 25 million shares worth almost $1 billion over the past week.

Berkshire Hathaway has steadily sold off 116 million Bank of America shares since July. But it still controls nearly 12% of the stock in the bank based in Charlotte, North Carolina.

After the sale was disclosed, Berkshire's Class A stock — already the most expensive stock on Wall Street — gained $7,184.62 Wednesday to sell for $698,534.62.

That elevated the conglomerate based in Omaha, Nebraska, into the club of companies valued by the stock market at over $1 trillion. But that's still well shy of market behemoths Nvidia and Microsoft, now valued at over $3 trillion.

The Bank of American stake remains one of Berkshire's biggest investments, behind only its large Apple stake and its longtime American Express investment.

Buffett raised eyebrows earlier this month when he revealed he had halved the Apple investment and in the process built up a record $277 billion cash pile as of June 30. Berkshire's cash has only grown since then with the Bank of America stock sales and all the earnings from the assortment of dozens of companies it owns, including BNSF railroad, Geico insurance, a collection of utilities and a bunch of retail and manufacturing businesses.

Buffett watchers say Berkshire's recent stock sales are likely a sign that the revered investor thinks the stock market is overpriced and they suggest he may be trying to set himself up to take advantage of a downturn.

Buffett never discusses why he is buying and selling certain stocks while he is doing it, and he hasn't offered any explanation for the Bank of America sales. He prefers to keep his moves close to his vest so other investors can't copy him, but the Securities and Exchange Commission requires him to file updates on Berkshire's Bank of America holdings because it owns more than 10% of the bank.

Buffett started selling off Berkshire's Bank of America shares after it peaked with a new 52-week high of $44.44 back in July. The latest sales were all made at average prices just under $40 a share.

The stock was up slightly Wednesday at $39.80.