NRG Energy rises after Buffett discloses stake

NEW YORK (Reuters) - NRG Energy Inc (NRG.N) shares rose as much as 6.7 percent on Friday after Warren Buffett's Berkshire Hathaway Inc (BRKa.N) (BRKb.N) revealed it had taken a stake in the independent power generator.

In a Thursday filing with the U.S. Securities and Exchange Commission, Berkshire said it owned 3.24 million shares of NRG as of June 30, a 1.4 percent worth $138.9 million at the time.

NRG is based in Princeton, New Jersey, but operates power generating facilities in Texas, as well as in the northeast, south central and western United States. Goldman Sachs & Co analysts on Thursday added NRG to its "conviction buy" list.

Buffett is the world's richest person, Forbes magazine said in March. Shares of companies often rise after Berkshire reveals stakes because many investors try to copy Buffett. NRG was Berkshire's only new reported stock investment in the second quarter, though Buffett spent $3.98 billion on equities.

Berkshire did not respond to a request for comment.

Omaha, Nebraska-based Berkshire generates about one-tenth of its earnings and revenue from utilities and energy, including its MidAmerican Energy Co unit.

Berkshire also made a confidential filing with the SEC regarding its stake in the oil company ConocoPhillips (COP.N). It reported a 17.51 million share stake three months earlier. The SEC regularly lets Buffett delay disclosing some of his investing activity so others cannot copy him.

Frank Betz, a principal at Carret/Zane Capital Management LLP in Warren, New Jersey, said energy is a conservative way for Buffett to generate steady, long-term growth. "It's easy to see him being active in energy," he said.

In Thursday's SEC filing, Berkshire also said it had lowered by 61 percent its stake in Anheuser-Busch Cos (BUD.N) before the brewer agreed to be acquired by Belgium's InBev NV INTB.BR.

It was not clear whether Berkshire cut its stake before or after InBev's interest in buying Anheuser surfaced in May.

Berkshire also revealed larger stakes in Sanofi-Aventis SA (SASY.PA), a French drugmaker, and Ingersoll-Rand Co (IR.N), which makes refrigeration and air-conditioning equipment. Ingersoll in June bought Trane Inc, another Berkshire holding.

Buffett, who turns 78 later this month, has built Berkshire into a $183 billion conglomerate with at least 76 companies offering such things as Fruit of the Loom underwear, Geico car insurance and See's candies, and investing in stocks such as Coca-Cola Co (KO.N) and Wells Fargo & Co (WFC.N).

In afternoon trading, NRG Energy shares were up $1.91, or 5.4 percent, at $37.13 on the New York Stock Exchange, after earlier rising to $37.59. Berkshire's Class A shares rose $2,400 to $118,600.

(Editing by John Wallace)