* JPMorgan gains, Wells Fargo and Citi drop after results
* J&J falls after verdict on asbestos cancer case
* AT&T drops as DoJ appeals Time Warner deal approval
* Futures: Dow up 4 pts, S&P up 1 pt, Nasdaq off 0.5 pts (Adds comment, details; updates prices)
By Amy Caren Daniel
July 13 (Reuters) - U.S. stock index futures were flat on Friday after a mixed bag of results from the three big Wall Street banks kicked off what is expected to be a strong corporate earnings season.
JPMorgan's shares rose 0.2 percent premarket after the lender's quarterly profit topped expectations due to strong trading revenue and as demand for loans increased on the back of a strengthening U.S. economy.
Wells Fargo shares slid 2.9 percent, having reversed course after reporting a bigger-than-expected drop in quarterly profit as lending activity slowed and it recorded higher expenses.
Citigroup shares fell 1.5 percent despite a profit beat on consumer banking strength.
The results from the banks kick off earnings season in earnest, with profits of S&P 500 companies expected to have surged around 21 percent in the second quarter, according to Thomson Reuters I/B/E/S.
"The set-up to go higher is in place, and the optimism around bank results and earnings is what is floating the markets right now," said Michael Antonelli, managing director, institutional sales trading at Robert W. Baird in Milwaukee.
However, investors and analysts will also keep an eye out for company forecasts and management commentary to gauge the impact of the U.S.-China trade war on results in the coming quarters.
Earlier in the day, data showed China's trade surplus with the United States swelled to a record in June as its overall exports grew at a solid pace, a result that could further inflame the bitter trade dispute with Washington.
At 8:58 a.m. ET, Dow e-minis were up 4 points, or 0.02 percent. S&P 500 e-minis were down 1.25 points, or 0.04 percent and Nasdaq 100 e-minis were down 0.5 points, or 0.01 percent.
"The optimism of Thursday's strong close was bound to get tested overnight, and when you have that big of a move you tend to have a some sort of a pullback going into the next session," said Antonelli.
Also weighing was Johnson & Johnson, which fell 2.2 percent after a jury ordered the Dow component to pay a record $4.69 billion to 22 women who alleged its talc-based products, contain asbestos and caused them to develop ovarian cancer.
AT&T Inc's shares fell 1.5 percent after the U.S. Justice Department said it would appeal a federal judge's approval of the telecom company's $85.4 billion acquisition of Time Warner, which has already closed. (Reporting by Amy Caren Daniel in Bengaluru; Editing by Shounak Dasgupta)