Before the bell: Stocks may open lower

U.S. stocks were headed for a weak open Tuesday, after Cisco announced impending job cuts, and Japanese officials raised the threat level at the Fukushima nuclear plant to the same as Chernobyl.

On Monday, U.S. stocks gave up an early advance and closed little changed, as investors look toward corporate reports due throughout the week.
Companies: Cisco Systems announced that it was taking a restructuring charge of $300 million, as it prepared to reduce its staff by 550 workers. Cisco (CSCO) shares dipped 1% on the news.
Alcoa (AA) kicked off earnings seasons with a first-quarter profit that beat estimates, but shares fell 3.3% in premarket trading, because the aluminum maker missed forecasts on revenue.
Economy: The Commerce Department released data on the U.S. trade balance for February, showing that the deficit narrowed to $45.8 billion, the gap was slightly more than expected.
Economists expected the report to show the trade deficit narrowed slightly to $45.7 billion, down from $46.3 billion in January.
World markets:

Oil for May delivery fell 29 cents to $109.63 a barrel.
Gold futures for June delivery fell $1.50 to $1,466.60 an ounce.
The price on the benchmark 10-year U.S. Treasury rose, pushing the yield down to 3.53% from 3.57% late Monday.