Falling home prices and a drop in retail sales weighed down the markets during the midday with the Dow dropping 55 points to 12,822. Nasdaq slipped a fraction to 2488.

On the upside

Canadian Solar (Nasdaq: CSIQ) reversed year ago losses to swing to a profit for the first quarter that beat expectations as European revenue surged. The solar cell maker also forecast second quarter results ahead of estimates.

Intercell AG offered $189 million, a 126% premium over the closing price on Monday, to purchase Iomai (Nasdaq: IOMI).

Third quarter earnings for Bally Technologies (NYSE: BYI) more than quadrupled to beat expectations as revenue climbed.

On the downside

Western Refining (NYSE: WNR) blamed record crude oil prices for swinging to a first quarter loss.

Bearing Point (NYSE: BE) cut its 2008 guidance prompting a downgrade.

NxStage Medical (Nasdaq: NXTM) blamed greater expenses for widening first quarter losses.

In the broad market, advancing issues outpaced decliners by a slim margin on the NYSE while decliners barely edged out advancers on Nasdaq. The Russell 2000 which tracks small cap stocks added 2 points to 735.