US stocks ended on a negative note after a choppy trading session on Tuesday, as investors remained cautious ahead of the Federal Open Market Committee meeting outcome due later today. The Dow Jones Industrial Average dropped almost 0.3 per cent to end at 45 thousand 758, the S&P 500 declined over 0.1 per cent to end at 6 thousand 607, while the tech-heavy Nasdaq Composite Index closed flat, with a slight negative bias, to settled at 22 thousand 334.