Department store operators outperformed after JPMorgan upgraded Kohl's ( KSS ) to outperform from neutral. Core consumer inflation, which excludes volatile oil and gas prices, increased 0.3%, a tad above expectations and an accelerating from 0.1% in November, but the market shrugged it off. In the stock market today , Facebook (FB) had a rough day, falling 4.5%, as Wall Street worried about the fundamental impact as a result of a change to the company's News Feed .