Tokyo, Aug. 21 (BridgeNews) - The Nikkei 225 Stock Average ended the morning session slightly lower, reversing gains made during early trade, despite the rebound on Wall Street overnight. Generally, investors stayed on the sidelines as they awaited the outcome of the Federal Reserve's Open Market Committee meeting due out later at about 1915 GMT. The Nikkei 225 Stock Average closed the morning down 22.20 points or 0.2% to 11,235.74.