Stocks ended off their session lows after sliding in the aftermath of a vote in Greece to reject more austerity measures. Some leaders suffered big losses. The S&P 500 lost 0.4% after being down as much as 0.9% at the start of trading. Energy stocks were an area of weakness for the benchmark index, as crude oil plunged nearly 8%. The Nasdaq trimmed a 1% loss to 0.3% but closed back below the 5000 mark.