Major U.S. stock-indexes rose on Tuesday as energy stocks rallied and Micron Technologies (MU.O) led tech stocks higher on reports of buyout interest. Twitter (TWTR) jumped as much as 8.5% to $38.82 after a report, purportedly from Bloomberg, that the company was made a $31 billion offer. The stock quickly gave up most of its gains after Bloomberg said the report was fake. Micron jumped as much as 12.4% 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 steadied after Iran and six global powers reached a landmark nuclear deal that left sanctions on the country in place for now, continuing to limit its crude exports. Oil prices had tumbled earlier on fears that the deal would ease sanctions, allowing more oil into the markets.

Almost all of Dow stocks in positive area (22 of 30). Top looser - Johnson & Johnson (JNJ, -0.76%). Top gainer - The Coca-Cola Company (KO, +1.41).

Almost all of S&P index sectors also in positive area. Top looser - Utilities (-0.1%). Top gainer - Healthcare (+0.9%).

At the moment:

Dow 17948.00 +48.00 +0.27%

S&P 500 2100.75 +6.25 +0.30%

Nasdaq 100 4518.25 +30.25 +0.67%

10-year yield 2.41% -0.02

Oil 53.00 +0.80 +1.53%

Gold 1154.90 -0.50 -0.04%