"Considerable uncertainty remains as to the ultimate outcome of these events," Berkshire said in the statement, referring to international trade policies and tariffs.
Buffett addressed the tariffs more directly at the company's annual meeting in Omaha, Nebraska.
"I think you can make some very good arguments for the fact that balanced trade is good for the world," Buffett said at the meeting."There is no question that trade can be an act of war."
He added that the US "should be looking to trade with the rest of the world."
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Berkshire said the majority of its businesses generated lower revenues and earnings in the first quarter. For Cathy Seifert, an analyst for CFRA Research, this may be a sign that the overall economy is softening.
"What we're seeing here is Berkshire's exposure to the broader economy, which is slowing," Seifert said in an interview.
The company declined to repurchase any of its own shares for the third quarter in a row. This could mean that the stock price is "too richly valued for Berkshire's taste," Seifert said.
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At the end of March, the company's five biggest holdings were still American Express Co., Apple Inc., Bank of America Corp., Coca-Cola Co. and Chevron Corp.
Berkshire Hathaway was a net seller of US$1.5 billion of equity securities in the quarter, according to the statement.
The insurance unit's investment income rose 11% to US$2.9 billion, boosted by a 31% increase in interest and other investment income as the conglomerate held more Treasury bills.
Geico, Berkshire's auto insurer, posted an increase in earnings as the unit continued to add more customers. Expenses also increased, as the insurer is trying to gain market share.
The insurance unit's underwriting earnings almost halved in the quarter, in part because of roughly US$860 million of after-tax losses tied to the California wildfires.
Berkshire's market value has hovered above US$1 trillion since late January, reaching a price-to-book ratio of 1.79 at the close of trading Friday.
