The European Central Bank halted refinancing operations with certain Greek banks. The markets traded mixed during the midday with the Dow rising 20 points to 12,652 while Nasdaq slipped 2 points to 2981.

On the upside

A Food and Drug Administration advisory committee unanimously recommended approval for OraSure Technologies' (Nasdaq: OSUR) OraQuick In-Home HIV Test.

SAC Capital has acquired more than 4.7 million shares of Goodyear Tire & Rubber (NYSE: GT) in the first quarter.

Legg Mason (NYSE: LM) will repurchase $1.25 billion in convertible senior notes and increased its stock buyback plan by an additional $1 billion.

On the downside

Velti (Nasdaq: VELT) narrowed first quarter losses more than expected as revenue surged but investors were disappointed that its full year guidance fell in line with expectations rather than surpassing analyst estimates.

Standard & Poor's downgraded Patriot Coal's (NYSE: PCX) credit rating to a B-.

Shares of Tata Motors (NYSE: TTM) fell after Mercedes-Benz unveiled the latest M-Class sport utility vehicle model for the Indian market.

In the broad market, declining issues barely edged out advancers by a slim margin on the NYSE and while advancers outpaced decliners by a narrow margin on Nasdaq. The Russell 2000 which tracks small cap stocks added a point to 778.