U.S. stock futures tumbled on Friday, erasing earlier gains, after the latest batch of inflation data showed producer prices accelerated faster than some economists expected last month. Futures for the Dow Jones Industrial Average DJIA, +0.30% were off 158 points, or 0.5%, at 33,885 after the data, erasing an earlier gain. Futures for the S&P 500 SPX, +0.73% tumbled 21 points, or 0.6%, to 3,944, while futures for the Nasdaq 100 were down 68.25 points, or 0.6%, to 33,885. The core producer price index rose 0.4% during the month of November, beating expectations for a 0.2% gain, while the headline PPI data came in at 0.3%, surpassing expectations for a 0.2% increase.