Berkshire also spent $1bn buying back its own shares in June, a commonly used tactic when Buffett and his investment team find fewer appealing targets in the market.
The 91-year-old investor signalled at the company's annual meeting in Omaha, Nebraska, in April that the spree of multibillion-dollar stock purchases was likely to slow as the year progressed, saying that the atmosphere in the company's 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 company and other big money managers disclose their investments to regulators.
Separate filings show the company has increased its stake in energy company Occidental Petroleum in recent months.
Berkshire's mammoth cash and Treasury holdings were little changed from the end of March, falling less than $1b to $105.4b.
While net income slid from a $5.5b profit at the year's start to a $43.8b loss, operating income — which excludes the ups and downs of Berkshire's stock positions — rose 39 per cent to $9.3b.
That included a $1.1b currency-related gain on its non-US dollar debt.
Berkshire is required to include the swings in the value of its stock and derivatives portfolio as part of its earnings each quarter, an accounting rule that Buffett has warned can make the company's earnings figures look "extremely misleading" and volatile.
The loss amounted to $29,754 per class A share. It stands in contrast to the $18,488 per share profit the company reported a year earlier.
Berkshire's results are parsed by analysts and investors for signs of the health of the broader US economy, as its businesses cut across much of the country's industrial and financial heart.
Inflationary pressures continued to bite, although many of its divisions were able to pass along higher prices to customers.
The BNSF railroad, which Buffett has described as one of the "four giants" within Berkshire, reported a 15 per cent increase in revenue as fuel surcharges it levied on clients offset a drop in shipping volumes.
Fuel costs for BNSF, which has over 32,500 miles of rail tracks across 28 states, jumped more than 80 per cent year on year.
Insurance unit Geico recorded a $487m pre-tax underwriting loss in the quarter, up from the three months before.
The division blamed the bigger loss on much higher prices for new cars and auto parts that it must pay when its clients are involved in accidents.
Buffett in April said the company was seeing the effects of inflation first hand, warning that it "swindles almost everybody".
Berkshire's housing businesses, including modular home unit Clayton Homes and home decor retailer Nebraska Furniture Mart, offered hints about how consumers were responding to higher prices and increased mortgage rates.
Furniture sales were relatively flat, with higher prices compensating for lower orders.
Nonetheless there were signs of strength in the housing market, with new housing sales from Clayton up 9.8 per cent in the first half of the year. Revenues for the division rose 28 per cent to $3.4b in the second quarter from a year earlier.
"The increases in home mortgage interest rates will very likely slow demand for new home construction, which could adversely impact our businesses," Berkshire warned.
"We also continue to be negatively affected by persistent supply chain disruptions and significant cost increases for many raw materials and other inputs, including energy, freight and labour."
Berkshire addressed a potential conflict raised at the company's annual meeting earlier this year.
In June it spent $870m to purchase shares that Berkshire vice chair Greg Abel, Buffett's anointed successor, held directly in its energy unit.
Abel joined the company in 2000 when Berkshire acquired the utility MidAmerican Energy, and had held part of his wealth in that business instead of in shares of the Berkshire parent company.
Shares of Berkshire Hathaway's class A common stock have fallen roughly 2 per cent this year, outperforming the 13 per cent drop in the benchmark S&P 500.
-By Eric Platt in New York
© 2022 The Financial Times Ltd.
