Stocks fell, closing out the Dow’s worst week of 2013. Markets were pulled lower by a weak performance from retailers and companies sensitive to higher interest rates. Home builders and banks were among the best performers. Overall, the Dow fell back 2.2 percent. The S&P lost 2.1 percent. A possible cutback in the Fed’s bond-buying program in September has roiled the bond market in the last couple of weeks, which has spilled over into stocks. Shares of utilities and telecom firms closed broadly lower. Retailers continued their selloff. And their outlooks have raised worries that US shoppers might be curbing their spending.