U.S. stocks rose on Tuesday following back-to-back daily declines, with merger activity more than offsetting market concerns as Greece struggles to avoid a default on its debt.

Citigroup Inc (C.N) and rivals in the commodity trade finance sector are facing headwinds of weak oil prices, sanctions on Russia and stiff competition, which have pressured fees.

European shares hit a near four-month low and yields on lower-rated euro zone sovereign debt climbed to their highest point since November, as financial markets braced for the possibility of Greece defaulting on its debt.

Botanical vaporizer manufacturer Pax Labs received $46.7 million in Series C financing from their investors to expand operation to the international market.

Last week, Asustek Computer Inc (Asus) chairman Johnny Shih in an internal company meeting had suggested that it may be a possibility to buy Taiwan-based smartphones and tablets manufacturer, HTC. However, HTC came out with its own statement on Monday, saying it will not consider a merger with Asus and also pointed out that no formal or informal talks had ever taken place in connection with the said acquisition.

To enhance passengers in-fight entertainment experience, United States-based airline carrier, Virgin America is introducing its latest version of its "Red system", which works on an Android platform and uses a high resolution multi-touch screen, like today's smartphones. The Android-based entertainment systems also gets more storage capacity, more games, improved maps and surround sound technology from startup Dysonics.

General Motors Co (GM.N) will re-enter the U.S. medium-duty truck market next year with Chevrolet-branded vehicles supplied by Japanese truck maker Isuzu Motors Ltd (7202.T), people familiar with the matter said on Monday.

The U.S. Federal Reserve is on track to raise interest rates for the first time in nearly a decade in September, according to a Reuters poll that suggests economists now are mostly confident about that timing.

Apparel retailer Gap Inc (GPS.N) said it would close a quarter of Gap specialty stores in North America over the next few years, including 140 this year, potentially affecting thousands of jobs as the company struggles with a slump in sales at its namesake brand.

Drugstore operator CVS Health Corp (CVS.N) will buy Target Corp's (TGT.N) pharmacies and clinics in a $1.9 billion deal that should help it bargain with drug makers for lower prices, while freeing Target from a costly business where it struggled to make a profit.