The Dow Jones Industrial Average gained 23.46 points (0.18 percent) to 12,804.41 in the first five minutes of trade. The broad-based S&P 500 added 1.13 points (0.08 percent) to 1,344.36, while the Nasdaq Composite rose 0.53 (0.02 percent) to 2,915.83. Positive signs for the US economy poured in, with the weekly report of new claims for unemployment benefits falling to their lowest level since March 2008 and data on January housing construction confirming a pickup in that depressed sector. But a Moody's warning of possible downgrades on scores of European banks and continued worries that Greece will not be able to fulfil requirements for a new bailout clouded the market.