U.S. stocks sank to a 15-month low, with the Standard & Poor's 500 Index tumbling below a low hit on Aug. 25, as the rout in oil persisted and data showing falling retail sales rekindled concern about the health of the economy.<br />"The growth picture in the U.S. is getting cloudier, and the fact that the Fed tightened in a weak environment is certainly not helping," said Krishna Memani, chief investment officer at Oppenheimer Funds Inc. in New York.<br />Corporate earnings may offer cues on the strength of the U.S. recovery, with seven S&P 500 companies posting results today.
