* Apple, Facebook, Amazon, Alphabet all drop
* JPMorgan up after Q4 results beat
* GoPro sinks on weak holiday-sales forecast
* Indexes down: Dow 0.26 pct, S&P 0.33 pct, Nasdaq 0.83 pct (Updates to open)
By Ankur Banerjee
Jan 14 (Reuters) - U.S. stocks fell on Thursday morning, extending a selloff from the day before as investors remained worried about weak energy prices, U.S. corporate earnings and the global economy.
Heavyweights Apple, Amazon, Facebook and Alphabet were all down more than 1.5 percent, weighing heavily on the S&P and the Nasdaq.
JPMorgan rose 0.8 percent to $57.77 on better-than-expected results, but failed to boost the financial sector.
Oil prices steadied, but remained near 12-year lows as the prospect of Iran's oil hitting an oversupplied market loomed.
At 9:57 a.m. ET (1457 GMT), the Dow Jones industrial average was down 42.11 points, or 0.26 percent, at 16,109.3.
The S&P 500 was down 6.22 points, or 0.33 percent, at 1,884.06 and the Nasdaq Composite index was down 37.38 points, or 0.83 percent, at 4,488.69.
"I think it's important to watch how the day plays out," said Art Hogan, chief market strategist at Wunderlich Securities in New York.
"We've seen this happen three days in a row where you get some positive action on the open and that fades pretty quickly into the day," Hogan said, adding that rallies have been selling opportunities this year.
The market has made multiple attempts at rallies this year, but concerns over China's economy, plunging oil prices and fresh global political concerns have stymied investors.
U.S. stocks sank on Wednesday, pushing the S&P 500 to close below 1,900 for the first time since September, on worries about weak energy prices, corporate earnings and the global economy.
Six of the 10 major S&P sectors were lower, led by a 1.3 percent drop in the consumer discretionary sector.
The utilities sector was the highest gainer, up 1.2 percent.
GoPro Inc slumped about 19 percent to $11.85 after the action camera maker estimated weak holiday-quarter revenue and said it would cut 7 percent of its workforce.
Best Buy dropped 10.5 percent to $26.24 after the electronics retailer reported disappointing holiday sales.
Chipotle was up 2.6 percent at $439.33 after the company expressed confidence in preventing future food poisoning outbreaks at its chains.
Intel is scheduled to report results after close.
Declining issues outnumbered advancing ones on the NYSE by 1,913 to 936. On the Nasdaq, 1,622 issues fell and 792 advanced.
The S&P 500 index showed no new 52-week highs and 98 new lows, while the Nasdaq recorded three new highs and 276 new lows. (Reporting by Ankur Banerjee in Bengaluru; Editing by Savio D'Souza)