Warren Buffett’s Berkshire Hathaway Inc. has sold an additional $982 million worth of Bank of America Corp. stock, continuing to reduce its stake in the second-largest U.S. bank. Since mid-July, Berkshire has trimmed its position by nearly 13%, generating a total of $5.4 billion in proceeds. The latest sales, disclosed in a regulatory filing, took place on August 23, 26, and 27. Despite the ongoing sell-off, Buffett has remained silent on his reasons for scaling back this highly profitable investment, which began when Bank of America shares were trading near $5 in 2011. Prior to these sales, the stock had risen 31% this year but has since dropped about 10% to $39.67.

This series of sales marks Buffett’s most significant retreat from an investment that has long been viewed as a vote of confidence in Bank of America’s CEO, Brian Moynihan, whom the 93-year-old investor has publicly praised on multiple occasions. Even after these disposals, Berkshire remains the bank’s largest shareholder, holding 903.8 million shares valued at $35.9 billion based on Tuesday’s closing price. Neither Berkshire nor Bank of America has commented on the sales, leaving the market to speculate on the motivations behind Buffett’s decision.