Stocks are closing out a skittish week on a sour note, falling sharply in the afternoon and giving the market its third straight week of declines, the AP reports. The day started out mixed on Wall Street Friday but a burst of selling through the afternoon left benchmark indexes solidly lower. Energy companies and banks bore the brunt of the selling as the price of crude oil fell. Southwestern Energy sank 5%. It was another bad day for retailers. Nordstrom plunged 13% after releasing disappointing quarterly results. The Dow Jones industrial average fell 185 points, or 1.1%, to 17,535. The Standard & Poor's 500 index gave up 17 points, or 0.9%, to 2,046. The Nasdaq composite index lost 19 points, or 0.4%, to 4,717. (More Dow Jones stories.)