Singapore shares were lower by midday Wednesday, with the index struggling near a four-month low and below its 200-day moving average.

The Straits Times Index (STI) was down 1.3 percent at 2,787.72 points, largely in line with weak regional markets on investor concern about the euro zone debt crisis. The STI fell below its 200-day moving average last week after staying above that level for more than three months.

CIMB Research said it remained overweight on the Singapore market, citing "decent valuations". It maintained its target of 3,340 points on the STI for the end of the first half of the year, based on a 2013 price-earnings ratio of 14 times.

The broker's top picks included CapitaCommercial Trust , which owns office and retail assets in Singapore, oil services firm Ezion Holdings Ltd and energy, water and marine group Sembcorp Industries Ltd.

Civil engineering company Swee Hong Ltd jumped 20 percent above its initial public offering price of S$0.225 on its trading debut. It was the third-highest traded stock by volume on the Singapore bourse.

By midday, Swee Hong shares were trading at S$0.27 on volume of 47.7 million shares.

1257 (0457 GMT)

(Reporting by Eveline Danubrata in Singapore; eveline.danubrata@thomsonreuters.com)