S&P 500 index posted a strong gains on Friday as investors bet on a positive outcome in Greek elections and awaited further actions regarding stimulus from global central banks. S&P 500 index added 1.03% or 13.74 points and finished at 1,342.84, the highest value since May 11. Energy shares climbed most. Wpx Energy soared 5.9% and Chesapeake Energy rallied 4.4%. Apple slightly improved by 0.5% to USD 574.13 a shares. On weekly basis US benchmark has ascended 1%.