By Reuters Staff 4 Min Read (Reuters) - The S&P 500 crossed the 4,000 mark for the first time on Thursday, jumping out of the gates for the second quarter with technology shares in the forefront and optimism about recovering U.S. growth, infrastructure spending and vaccines undergirding sentiment. STORY: * STOCKS: S&P 500 up 0.94% AT 4,010, Dow up 0.48%, Nasdaq up 1.54% * BONDS: Benchmark 10-year notes last rose 20/32 in price to yield 1.6752%, from 1.746% late on Friday. * FOREX: The dollar index fell 0.291%, with the euro up 0.35% to $1.1769.