S&P 500 index closed lower on Friday pushed down by energy shares. US benchmark index lost 0.33% or 4.46 points and closed at 1,369.63. Big Lots tumbled 4% after retailer lowered its earnings forecasts. Peabody Energy slumped 6.5% after Iranian media said an explosion took place at Saudi Arabia pipeline. Saudi Arabia rejected the news. Alpha Natural Resources fell 5.7% after Moody's downgraded company's credit rating outlook from stable to negative citing accelerating costs and weaker demand for coal.