Singapore’s Straits Times Index fell 0.3% to 3,148.27 as of the 12:30 p.m. trading break, reversing a two-day gain of 1.9%. Fifteen stocks fell and 12 rose on the 30-member gauge.

Shares on the measure trade at an average 15.4 times estimated earnings, compared with about 17.4 times at the beginning of the year, according to data compiled by Bloomberg.

The following shares are among the most active in the market. Stock symbols are in parentheses after company names.

Commodity suppliers: The Reuters/Jefferies CRB Index, which tracks prices of 19 commodities from copper to corn, fell 0.6% New York.

Noble Group (NOBL SP), a Hong Kong-based commodities supplier, slipped 0.5% to $1.92. Olam International (OLAM SP), one of the world’s three biggest suppliers of cotton, lost 3.9% to $3.18. Olam was also cut to “hold” from “buy” by Kim Eng Securities Pte yesterday.

Boustead Singapore (BOCS SP), a provider of engineering services, rose 0.5% to 99.5 Singapore cents. The company said its energy-related unit won contracts from the oil and gas industries in Brazil and Chile for $9 million.

Rotary Engineering (RTRY SP) gained 3.2% to 97 cents. The provider of engineering design and construction services for plants was rated “buy” in new coverage by Phillip Securities Pte, which set its share price estimate at $1.35.

SIA Engineering Co. (SIE SP), the aircraft maintenance unit of Singapore Airlines (SIA SP), rose 1.6% to $4.58. The company said it signed a contract with Airbus to provide maintenance services for five Singapore Airlines fleets. SIA was also rated “buy” in initial coverage by Royal Bank of Scotland Group Plc. The share price estimate was set at $4.

Yongnam Holdings (YNH SP), a Singapore-based construction company, surged 15% to 31 cents. The company’s investment rating was rated “buy” in initial coverage by DBS Group Holdings, and its share price target was set at 45 cents.