(Recasts first paragraph, adds financial details throughout)
By Jonathan Stempel
Aug 4 (Reuters) - Berkshire Hathaway Inc, the conglomerate run by billionaire Warren Buffett, on Saturday said quarterly operating profit rose 67 percent, as insurance underwriting rebounded and several business units benefited from a growing economy.
Results easily topped analyst forecasts. Underwriting profit at the Geico auto insurance unit more than quintupled, the BNSF railroad benefited from demand to ship consumer products, grain, petroleum and steel, and the Berkshire Hathaway Automotive car dealership financed more vehicle purchases.
"Good results across the board," said Doug Kass, who runs the hedge fund Seabreeze Partners Management Inc in Palm Beach, Florida. He has previously sold Berkshire shares short, betting on a decline, but is not doing so now.
Berkshire also said second-quarter net income nearly tripled, though that reflected a new accounting rule requiring it to report unrealized investment gains with earnings. Buffett says the rule distorts net results and can mislead investors.
Operating profit rose to $6.89 billion, or roughly $4,190 per Class A share, from $4.12 billion, or $2,505 per share, a year earlier.
Analysts on average expected operating profit of $3,387 per share, according to Thomson Reuters I/B/E/S.
Net income rose to $12.01 billion, or $7,301 per Class A share, from $4.26 billion, or $2,592 per share, a year earlier.
Results also reflected a decline in Berkshire's effective income tax rate to 20 percent from 28.9 percent, following last year's cut in the federal corporate tax rate.
Berkshire is based in Omaha, Nebraska, and has more than 90 businesses in the insurance, chemicals, energy, food and retail, industrial parts, railroad and other sectors.
Their day-to-day operations are overseen by Greg Abel and Ajit Jain, each seen by investors as a possible successor to Buffett, 87, as chief executive. Buffett and Vice Chairman Charlie Munger, 94, handle major capital allocation decisions.
Book value per Class A share, reflecting assets minus liabilities and a preferred measure of growth for Buffett, rose 3 percent in the quarter to $217,677.
Berkshire also ended June with $111.1 billion of cash and equivalents, some of which Buffett could use to repurchase stock under a new policy giving him and Munger more freedom to buy back stock they considered undervalued.
The change reflected Buffett's inability to find big acquisitions since January 2016, when Berkshire paid $32.1 billion for aircraft parts maker Precision Castparts.
Buffett has not bought back stock in 2018, but has spent money on stocks, and Berkshire said it ended June with a $47.2 billion stake in Apple Inc.
Apple's share price at the time suggests that Berkshire may have bought about 15 million Apple shares in the second quarter, on top of 239.6 million it already owned.
The iPhone maker this week became the first U.S.-listed company whose stock market value topped $1 trillion.
Berkshire spent $6.08 billion on equities in the quarter. It did not immediately respond to a request for comment.
Class A shares of Berkshire closed Friday at $304,671, or 7 percent below their Jan. 29 peak, while Class B shares closed at $200.24, or 8 percent below their peak the same day.
Insurance underwriting profit totaled $943 million, compared with a year earlier $22 million loss.
Geico's pre-tax underwriting profit rose to $673 million from $119 million, after it boosted rates in response to rising accident and storm losses.
Float, or insurance premiums collected before claims are paid and which help fund Berkshire's growth, ended June at $116 billion.
BNSF profit surged 37 percent to $1.31 billion, as economic growth led to more shipments of consumer goods, and demand for fertilizer, grain, petroleum products, plastics, sand and steel.
Profit from manufacturing, services and retailing units rose 29 percent, reflecting demand at Precision Castparts, Berkshire Hathaway Automotive and the German motorcycle accessories unit Detlev Louis Motorrad.
Meanwhile, tax credits for wind-powered electricity generation helped boost profit 14 percent at Berkshire Hathaway Energy. (Reporting by Jonathan Stempel in New York; Additional reporting by Jennifer Ablan; Editing by James Dalgleish)