NEW YORK (MarketWatch) — U.S. stocks wrapped up a solid year on a down note, erasing early gains to end with sizable losses Wednesday. The S&P 500 SPX, -1.03% fell 21.45 points, or 1%, to finish 2014 at 2,058.90, according to early FactSet data. The benchmark gained 11.4% for the year. The Dow Jones Industrial Average DJIA, -0.89% slid 160 points, or 0.9%, to end at 17,823.07, leaving the blue-chip gauge with a 7.5% rise for the year. Some market watchers said there was no single factor behind the stock market’s choppy action on Wednesday, and investors shouldn’t read that much into its moves on light, pre-holiday volume. But others suggested typical end-of-quarter action occurred, where portfolio managers bid up stocks in the morning, then ran out of money and walked away, leaving equities vulnerable for an afternoon fade.