The steepest fall in oil prices in more than three years pulled energy stocks lower on Wall Street, extending a losing streak for the S&P 500 index to a fourth day, the AP reports. The price of US crude plunged 7.1% Tuesday, to $55 a barrel, the lowest since December 2017. Oil has now fallen for 12 straight days, driven by worries over rising oil production around the world and weakening demand from developing countries. Energy companies sustained big losses. Exxon Mobil gave up 2.3%. The S&P 500 fell 4 points, or 0.1%, to 2,722. The Dow Jones Industrial Average lost 100 points, or 0.4%, to 25,286. The Nasdaq composite was little changed at 7,200. (More stock market stories.)