S&P set for biggest gain in 16 years; U.S. stocks post mixed results

The Standard & Poor’s 500 Index is poised to post its biggest annual gain since 1997 as several U.S. stocks fluctuated, according to Bloomberg News.

The S&P hit an all-time high last week and is poised to climb 29 percent in 2013, having jumped 3.7 percent alone between Dec. 13 and Dec. 27. The S&P is up 172 percent since it hit a 12-year low in 2009.

However, several notable U.S. stocks posted mixed results recently, according to Bloomberg. Twitter Inc. (NYSE: TWTR) dropped 7.1 percent since Dec. 27, when the stock fell 13 percent. Facebook Inc. (Nasdaq: FB) declined 2.6 percent during the same period, while Walt Disney Co. (NYSE: DIS) notched up 2.3 percent following an analyst upgrade.

Read more from Bloomberg.