Shares on the Singapore stock market slid on Wednesday as investors awaited economic growth data from the United States and the outcome of the US Federal Reserve's latest policy meeting.

The benchmark Straits Times Index lost 23.5 points, or 0.72 per cent, to 3,221.9, joining regional markets such as Tokyo, Taiwan, Seoul and Hong Kong in the red.

Shanghai bucked the trend, gaining 0.2 per cent on pledges by its government to stabilise growth while continuing with economic reforms.

In Singapore, stocks that fell outnumbered those that rose 307 to 139. Another 355 counters were unchanged.

A total of 2.3 billion shares changed hands on Wednesday, with a combined value of $1.68 billion.

Top gainers included property developer UOL, which rose 21 cents to $6.98. Insurance group Great Eastern was among the top losers, shedding 41 cents to $17.30 after it posted a 77 per cent drop in second-quarter net profit on Wednesday morning before the market opened.