The Sensex and Nifty ended lower on Wednesday amid mixed global market trends ahead of the keenly awaited US Fed interest rate decision. The US central bank is expected to raise its key short-term rate by a substantial three-quarters of a point for the third consecutive time. Another hike that large would boost its benchmark rate — which affects many consumer and business loans — to a range of 3% to 3.25%, the highest level in 14 years.