ToplineWall Street got cold feet Thursday ahead of a key speech from Federal Reserve Chairman Jerome Powell, with major indexes registering their worst days in weeks. Slow your roll: The S&P 500 came within 0.5% of its all-time high Thursday morning before turning ... [+] negative.Getty Images Key FactsThe blue chip Dow Jones Industrial Average fell 0.4%, or 164 points, the benchmark S&P 500 declined 0.9% and the tech-heavy Nasdaq Composite lost 1.7%. It’s the S&P and Nasdaq’s steepest daily losses since A ...