* Oil prices recover some ground after tumbling earlier
* Twitter retreats after buyout report said to be fake
* JPMorgan profit beats estimates; Wells Fargo revenue misses
* Amazon hits record high on UBS upgrade
* Indexes up: Dow 0.35 pct, S&P 0.38 pct, Nasdaq 0.66 pct (Updates to early afternoon)
By Tanya Agrawal
July 14 (Reuters) - Wall Street was higher in early afternoon trading on Tuesday, led by a rally in healthcare stocks and as energy stocks rose after oil prices recovered on easing fears of higher crude supplies due to the Iran nuclear deal.
Twitter jumped as much as 8.5 percent after a report, purportedly from Bloomberg, that the company was made a $31 billion offer. Bloomberg and Twitter said the report was fake and the stock quickly gave up most of its gains to trade up 3 percent at $36.86.
Micron Technology jumped as much as 12.7 percent to $19.84 and was the biggest gainer on the S&P 500. China's state-backed Tsinghua Unigroup Ltd is preparing a $23 billion bid for the U.S. memory chip maker, Reuters reported, in what would be the biggest Chinese takeover of a U.S. company.
Oil prices reversed course from session lows after Iran and six global powers reached a nuclear deal, but left sanctions on the country in place for now, continuing to limit its crude exports. Oil prices had tumbled on fears that the deal would ease sanctions, allowing more crude into the markets.
"The market was short going into the Iran agreement, but the bears did not get the selloff they were hoping, so we're going back up," said Scott Shelton, commodities specialist and crude broker with ICAP in Durham, North Carolina.
Energy stocks rose as Brent and U.S. crude both rose strongly. Some investors however feel Tuesday's rally will be short-lived and longer-term prospects look dim given excess crude supplies.
At 13:12 p.m. ET (1712 GMT) the Dow Jones industrial average was up 63.3 points, or 0.35 percent, at 18,040.98. The S&P 500 was up 7.91 points, or 0.38 percent, at 2,107.51 and the Nasdaq composite was up 33.46 points, or 0.66 percent, at 5,104.97.
Nine of the 10 major S&P 500 sectors were higher, with the health index's 0.65 percent rise leading the advancers. The Nasdaq biotech index touched a record high.
Investors have also shifted focus to U.S. corporate earnings as worries about Greece and China abate, for the time being at least.
U.S. companies are expected to report their worst sales decline in nearly six years when they post second-quarter results, while earnings are expected to have fallen 2.9 percent, according to Thomson Reuters estimates data.
Investors are ignoring external worries such as China's economic slowdown for the time being and focusing on earnings, said Robert Lutts, chief investment officer at Cabot Wealth Management in Salem, Massachusetts which oversees $600 million.
"We are in the after glow of the Greece and Iran deals," Lutts said. "Earnings expectations are pretty modest right now. If the stock market is going to get any help from earnings, we need to see better growth."
JPMorgan and Wells Fargo kicked off the quarterly earnings season. JPMorgan was up 1.1 percent at $68.84 and Wells Fargo was up 0.8 percent at $57.17.
Amazon rose to a record high of $467.64 after UBS upgraded the company's stock to "buy" from "neutral".
Advancing issues outnumbered decliners on the NYSE by 1,866 to 1,109. On the Nasdaq, 1,692 issues rose and 1,009 fell.
The S&P 500 index posted 35 new 52-week highs and two new lows, while the Nasdaq recorded 106 new highs and 25 new lows. (Editing by Savio D'Souza)