U.S. stocks end mixed amid oil volatility, earnings reports

U.S. stocks close narrowly mixed Thursday, as investors eyed choppy trading in oil market while digesting quarterly earnings reports.

By midday, the Dow Jones Industrial Average rose 62.63 points, or 0.35 percent, to 17,713.89. The S&P 500 increased 6.18 points, or 0.30 percent, to 2,057.30. The Nasdaq Composite Index added 13.18 points, or 0.28 percent, to 4,738.82.

Oil prices pared most of early gains to settle mildly higher Thursday amid worries over a near-term supply shortage caused by a huge wildfire near Canada's oil sands reservoir.

In corporate news, shares of Alibaba soared 3.97 percent to 78.83 U.S. dollars apiece Thursday after the China-based e-commerce giant delivered upbeat quarterly results.

Alibaba's revenue for the quarter ended March 31 was 3,751 million dollars, an increase of 39 percent year-over-year, and mobile revenue was 2,029 million dollars, an increase of 149 percent year-over-year.

Shares of Merck declined 1.31 percent to 54.09 dollars apiece Thursday after the U.S. drug maker posted quarterly earnings above estimates but revenue shy of forecasts.

On the economic front, in the week ending April 30, the advance figure for seasonally adjusted initial jobless claims was 274,000, an increase of 17,000 from the previous week's unrevised number of 257,000, said the U.S. Labor Department on Thursday.

The four-week moving average was 258,000, an increase of 2,000 from the previous week's unrevised average of 256,000.

Meanwhile, investors kept a close eye on Friday's nonfarm jobs report for more clues on the Federal Reserve's next rate hike. Enditem