Berkshire said on Saturday that the slump in global financial markets had weighed heavily on its stock portfolio, which fell in value to $328 billion from $391 billion at the end of March. The $53 billion loss far exceeded an upbeat quarter for its businesses, which improved their profitability. The company’s filing with U.S. securities regulators showed that its purchases of new shares fell to about $6.2 billion in the quarter, from the $51.1 billion it spent between January and March – a surge that surprised Berkshire shareholders. Berkshire sold $2.3 billion worth of stock in the last quarter. Berkshire also spent $1 billion to buy back shares in June, a tactic typically used when Buffett and his investment team can find less attractive targets in the market. The 91-year-old investor signaled at the firm’s annual meeting in Omaha in April that the multibillion-dollar stock-buying spree was likely to slow as the year went on, saying the atmosphere at corporate headquarters had become more “lethargic.” Investors will get a more detailed update on how Berkshire’s stock portfolio has changed later this month, when the firm and other big money managers disclose their investments to regulators. Separate filings show the company has increased its stake in energy firm Occidental Petroleum in recent months.

Investing in the quarter meant Berkshire’s mammoth cash and Treasury holdings were little changed from late March, falling less than $1 billion to $105.4 billion. While net income fell from a profit of $5.5 billion at the start of the year to a loss of $43.8 billion, operating income — which excludes the top and bottom of Berkshire’s equity positions — rose 39 percent to 9 $.3 billion. Berkshire is required to include fluctuations in the value of its portfolio of stocks and derivatives as part of its earnings each quarter, an accounting rule that Buffett has warned can make the company’s earnings figures look “extremely misleading.”