The Sensex at the Bombay Stock Exchange declined 76 points, or 0.4 per cent, to close at 19,667, today, as investors trimmed their positions ahead of the quarterly corporate earning season. The Nifty at the National Stock Exchange fell 30 points, or 0.5 percent, to 5,972.But stock markets in Japan, Hong Kong, and Singapore gained about 0.5 percent, each.