US STOCKS-Futures flat after volatile week, oil down again
* S&P may be poised for third straight weekly decline
* Consumer sentiment data on tap after market open
* FXCM rallies in premarket after strong results
* Futures up: Dow 14 pts, S&P 2.25 pts, Nasdaq 7.75 pts
By Ryan Vlastelica
NEW YORK, March 13 (Reuters) - U.S. stock index futures were little changed on Friday as investors held off on making bets following a volatile week that was marked by sharp swings in both directions.
* The S&P 500 posted its biggest one-day gain since early February on Thursday, a rally that was offset by the biggest one-day loss since early January on Tuesday.
* Equities have recently been driven by the U.S. dollar, with the S&P having a high inverse correlation to the currency. Thursday's equity rally corresponded with the biggest one-day drop in the U.S. dollar index in a month.
* The dollar index is up almost 2 percent this week and is on track for its fourth straight weekly advance. Investors see the continued strength in the greenback as a threat to multinational corporate profits. The index rose 0.1 percent on Friday. Continuación...