Warren Buffett’s Berkshire Hathaway sold a portion of its Bank of America Corp. shares this week, bringing its stake in the bank just below 10%, a key regulatory threshold. After the lender repurchased $3.5 billion of its own shares in the third quarter, Berkshire’s stake had crept back above 10%, prompting the sale. This marks the 16th round of stock disposals by Buffett since mid-July, generating around $370 million. Berkshire’s stake now stands at 9.97%.

Under US regulations, investors holding over 10% of a company must disclose their trades within days, but now that Berkshire’s stake has fallen below that level, further stock sales could go unreported for months. Despite trimming its position, Berkshire remains Bank of America’s largest shareholder, with a stake valued at approximately $32.6 billion as of Thursday's close. Buffett has not commented on the decision to reduce his investment, though his initial $5 billion investment in 2011 has remained a cornerstone of his portfolio for years.