NEW YORK -Wall Street lost ground on Tuesday, with risk-off sentiment weighing as the U.S. Federal Reserve convened for its much-anticipated two-day monetary policy meeting. All three indexes ended the session lower in a broad sell-off ahead of the Fed's interest rate announcement on Wednesday, which is expected to culminate in a decision to leave key interest rates unchanged. "It's a big set up coming into tomorrow andmarkets are clearly focused on any change in communication from the Federal Reserve," said Bill Northey, senior investment director at U.S. Bank Wealth Management in Helena Montana, who expects "intense focus on the Fed's perspective on inflation in the post-meeting ...Keep on reading: U.S. stocks close lower as investors take cover ahead of Fed decision