Investing.com - U.S. stock index futures were flat Friday ahead of U.S. Q4 preliminary GDP data. The Dow futures was unchanged at 06:45 ET as the DJI held onto the 20,000 mark overnight. TheS&P 500 futures fell 0.04%. The tech-heavy Nasdaq 100 futures added 0.04%. U.S. economic growth is expected to have slowed to 2.2% in the fourth quarter of last year. The dollar was firm as a possible trade war between Mexico and the U.S. loomed over Trump's border wall plans. Google (NASDAQ:GOOGL) parent (NASDAQ:Alphabet) and (NASDAQ:Microsoft) in focus after Q4 earnings reports.