OMAHA (Bloomberg) — Billionaire investor Warren Buffett's Berkshire Hathaway Inc. said third-quarter profit surged 64 percent after gains from its investment in PetroChina Co.

Net income increased to $4.55 billion as investment and derivative gains increased more than tenfold to $1.99 billion after taxes, the Omaha, Nebraska-based company said on Friday. Berkshire began selling its 2.34 billion PetroChina shares when oil reached $75 a barrel in the quarter.

Buffett, 77, is investing outside the US to spur profit growth at his $200 billion investment and holding company as insurance profit wanes. Results were helped by Israel-based subsidiary Iscar Metalworking Cos., acquired for $4 billion last year in Buffett's first purchase of a non-US company. PetroChina rose more than eightfold since Berkshire's $488 million investment in 2003.

"I don't think anybody's ever made much money betting against Warren Buffett and Berkshire Hathaway," said Frank Betz, who helps manage $800 million, including Berkshire shares, at Carret Zane Capital Management in Warren, New Jersey. "His investment in China was the big brass ring that he grabbed in this period."

Excluding investment gains, Berkshire's profit fell 1.4 percent to $2.56 billion, or $1,655 a share. Gary Ransom, an analyst at Fox-Pitt Kelton Cochran Caronia Waller had forecast $1,477 a share because of the expected drop in insurance earnings, Berkshire's biggest business. Ransom rates the stock "in-line".

Buffett, ranked the world's third-richest man by Forbes magazine, transformed Berkshire from a failing textile maker into an enterprise with businesses ranging from ice cream and underwear to corporate jet leasing. He has another $60 billion for purchases, and said as recently as last week that he's "still negative" on the dollar and likes to get "foreign-exchange exposure through stocks".

Underwriting profit from units including National Indemnity Co. and Geico Corp. tumbled 47 percent to $486 million. Buffett has told investors not to expect a repeat of the $3.8 billion in insurance earnings in 2006 when the company charged record rates a year after Hurricane Katrina. Falling prices after a calm 2006 hurricane season led Berkshire to scale back catastrophe coverage this year.

Berkshire Hathaway Reinsurance Group, which includes the catastrophe reinsurance business of National Indemnity, earned $183 million before taxes, down 75 percent.

Reinsurance broker Willis Group Holdings Ltd. estimates that the cost of property reinsurance sold as of July 1 declined 15 percent to 20 percent on average from a year earlier.