By Dan Weil The S&P; 500 has climbed 8.5% since June 15 and 4.7% since July 26, loosening financial conditions. After dropping for the first 5 ½ months of the year, the S&P 500 has rebounded 8.5% since June 15 and 4.7% since July 26, the day before the Federal Reserve raised interest rates. Investors have turned enthusiastic toward stocks partly because Fed Chairman Jerome Powell said after the rate hike that the central bank will eventually slow its rate hike campaign. And the July 28 news that GDP contracted an annualized 0.9% in the second quarter led investors to conclude that the Fed migh…