The stock market marched past another milepost on its long journey back from the Great Recession as the S&P 500 closed at a new high Thursday, three weeks after the Dow passed its own closing record. The numbers offer more evidence that investors believe the economy is on the mend, said one chief equity strategist. Thursday’s performance was driven by encouraging economic data and the fact that many companies are posting record profits. The Fed has helped also by keeping interest rates near record lows. Cyprus reopened its banks after closing them for nearly two weeks to keep depositors from making panicked withdrawals.