* Powell to testify before Congress at 10.00 a.m. ET
* Netflix sinks on subscriber miss, weighs on tech stocks
* Amazon falls as tech glitch hurts prime day
* UNH drops as medical costs rise; J&J gains on profit beat
* Futures: Dow flat, S&P dips 0.11 pct, Nasdaq down 0.13 pct (Adds comment, details; updates prices)
By Amy Caren Daniel
July 17 (Reuters) - U.S. stocks were set to open lower on Tuesday as Netflix slumped after reporting weak subscriber growth and weighed on other technology stocks and as investors awaited Federal Reserve Chairman Jerome Powell's Congressional testimony.
Netflix sank 12.8 percent after the company's quarterly subscriber growth missed analysts' expectations, fanning fears that its rapid expansion is slowing.
Amazon.com fell 0.6 percent after it suffered a technology glitch during its summer marketing event, Prime Day.
Netflix and Amazon weighed on the so-called FAANG group, with Facebook, Apple and Google-Parent Alphabet down between 0.3 percent and 0.9 percent.
Fed Chairman Powell's testimony on the economy and monetary policy before the U.S. Senate Banking Committee will be released at 10.00 a.m. ET and he will answer questions from the House of Representatives Financial Services Committee on Wednesday.
Powell is likely to reiterate the Fed's stance towards gradual monetary policy tightening. Markets will focus on his views on recent trade tensions.
"The main focus of the day will be Powell's presentation of the monetary policy," said Peter Cardillo, chief market economist at Spartan Capital Securities in New York.
"Investors will be listening very closely at what he's going to say and see if he addresses the implications of tariffs on economic growth."
While earnings at S&P 500 companies are expected to have surged about 21 percent in the second quarter, traders and analysts are focusing more on company forecasts to gauge if the growth can be sustained, especially as the U.S.-China trade dispute escalates.
At 8:44 a.m. ET, Dow e-minis were up 2 points, or 0.01 percent. S&P 500 e-minis were down 3 points, or 0.11 percent and Nasdaq 100 e-minis were down 9.75 points, or 0.13 percent.
UnitedHealth dropped 1.7 percent after the largest U.S. health insurer's quarterly medical costs was slightly higher than expectations.
But fellow healthcare company and Dow component Johnson & Johnson rose 1.4 percent after it beat quarterly profit estimates.
Goldman Sachs rose 0.6 percent as growth in bond trading and investment banking drove a profit beat. The bank also said David Solomon would replace Lloyd Blankfein as chief executive.
Netflix's report also weighed on shares of other streaming companies, with Spotify down 2.2 percent and Twitter dropping 1.1 percent.
Economic data due at 9.15 a.m. includes a report that is expected to show industrial production rose 0.6 percent in June, after dipping 0.1 percent in May. (Reporting by Amy Caren Daniel in Bengaluru; Editing by Arun Koyyur)