Wall Street sold utility, tech and consumer-staples stocks Thursday, driving U.S. equities south in the final trading day of 2015 and threatening to end the S&P 500 index’s yearly winning streak. A continued slump in crude-oil prices helped pressure stocks early in the session, but even as crude turned somewhat higher stocks remained in a slump. The S&P 500 index SPX, -0.54% was 14 points, or 0.7%, lower at 2,048, leaving the index down 0.4% for the year. The Dow Jones Industrial Average DJIA, -0.62% was 133 points, or 0.8%, lower at 17,470, led by a 1.3% slump in shares of Apple Inc. AAPL, -1.41% A fourth straight year of gains was on the line for the S&P 500. Technology and consumer-staples and utilities were all showing sharp losses of greater than 1%.