U.S. stock indexes fell on Tuesday ahead of Federal Reserve Chair Jerome Powell’s testimony that may offer fresh insight on policy tightening and the central bank’s plans to tackle inflation. Powell is set to appear before the Senate Banking Committee at 10 a.m ET for consideration for a second four-year term as head of the Fed, while Lael Brainard is set to appear before the same panel on Thursday for promotion to a four-year term as Fed vice chair. “I believe Powell will stick to his script, as he generally is disciplined enough to do and I’m not expecting anything that would surprise markets,” said David Bahnsen, chief investment officer at the Bahnsen Group. The S&P 500 index is on course to fall for its sixth straight session, while the Nasdaq gave back gains from Monday as big tech stocks were subdued. Ten of the 11 S&P 500 sectors were …