Singapore shares may open lower on Wednesday after Wall Street fell overnight as news that Portugal's debt could be downgraded reignited selling.

Singapore’s benchmark Straits Times Index <.FTSTI> fell 0.43% on Tuesday to close at 3,144.70 points.

Stocks and factors to watch, say Thomson Reuters and Bloomberg:

Bulk-shipping companies: The Baltic Dry Index, which measures the cost of shipping commodities, fell 2.1% in London yesterday, extending its four-day decline to 5.2%. Cosco Corp. Singapore (COS SP), a China-based shipbuilder that also operates bulk carriers, slipped 1.5% to $2.02. STX Pan Ocean Co. (STX SP), South Korea’s biggest bulk carrier, gained 0.2% to $13.68.

Singapore Airlines (SIAL.SI) may be in focus after its cargo division agreed to plead guilty in a US price-fixing case and pay a US$48 million criminal fine, the US Justice Department said on Tuesday.

Amtek Engineering (AMEL.SI), a manufacturer of precision metal, plastic and rubber components, will debut on the Singapore stock exchange at 9:00 a.m. The firm said on Tuesday it had sold 200 million shares at $1.30 each.