S&P 500 index extended downward path on Wednesday as oil prices tumbled and orders for durable goods in US rose only 2.2% compared to predicted 2.9% gain. US benchmark gauge lost 0.49% or 6.98 points and closed at 1,405.54. Medco Health Solutions rallied 3.2% on news it may be acquired by Express Scripts, a deal worth about USD 29 billion. Oil shares fell as crude supplies increased. Peabody Energy shed 3.4% and Tesoro Petroleum dropped 2.5%.