* Oil prices highest in six months
* Apple rises after Buffett reports stake in company
* Anacor Pharma jumps after receiving $5.2 bln buyout offer
* Indexes up: Dow 0.80 pct, S&P 0.78 pct, Nasdaq 1 pct (Updates to early afternoon)
By Tanya Agrawal
May 16 (Reuters) - Wall Street rose in early afternoon trading on Monday, bolstered by a jump in Apple shares and gains in energy stocks.
The iPhone maker's shares were up 3.4 percent after Warren Buffett's Berkshire Hathaway reported a stake worth about $1 billion in the company. The stock gave the biggest boost to the three indexes.
Oil jumped more than 3 percent to its highest in six months due to disruptions in Nigerian output and after long-time bear Goldman Sachs said the market had ended almost two years of oversupply and flipped to a deficit.
U.S. stocks fell on Friday as gloomy quarterly reports from retailers overshadowed upbeat April retail sales data, leaving the Dow and the S&P 500 lower for the third straight week.
The retail sector is in focus again, with Wal-Mart, Home Depot and Target scheduled to report quarterly results this week.
"Some acquisitions, news of Berkshire taking a stake in Apple and higher oil prices are driving the market," said Paul Nolte, portfolio manager at Kingsview Asset Management in Chicago.
"I think the markets should stay here most of the day."
At 12:40 p.m. ET (1640 GMT) the Dow Jones industrial average was up 140.43 points, or 0.8 percent, at 17,675.75, the S&P 500 was up 16.05 points, or 0.78 percent, at 2,062.66 and the Nasdaq Composite was up 46.99 points, or 1 percent, at 4,764.67.
Nine of the 10 major S&P 500 sectors were higher, with the energy index's 1.61 percent rise leading the gainers.
Exxon was up 0.9 percent and Chevron 1.4 percent.
While the S&P 500 has risen about 15 percent since February lows, the rally fizzled out in the last few weeks due to disappointing corporate earnings and mixed economic data.
Tribune Publishing was up 22.1 percent at $14 after Gannett raised its buyout offer to $15 per share. Gannett was up 1.7 percent at $15.89.
Anacor Pharmaceuticals soared 55.2 percent to $99.38 after Pfizer said it would buy the drugmaker in a deal valued at $5.2 billion. Pfizer was little changed at $33.22.
Memorial Resource Development jumped 5.4 percent to $14.15 after Range Resources said it would buy fellow oil and gas producer for about $3.3 billion. Range Resources was down 8.9 percent at $38.29
Advancing issues outnumbered decliners on the NYSE by 2,349 to 596. On the Nasdaq, 1,966 issues rose and 790 fell.
The S&P 500 index showed 11 new 52-week highs and three new low, while the Nasdaq recorded 31 new highs and 43 new lows. (Reporting by Tanya Agrawal and Yashaswini Swamynathan; Editing by Anil D'Silva)