Rising unemployment sent the markets tumbling during the midday with the Dow plunging 148 points to 12,909. Nasdaq plummeted 61 points to 2542.

On the upside

Human Genome Sciences (Nasdaq: HGSI) will be presenting an overview of the company at the 26th Annual JPMorgan Healthcare Conference.

Goldman Sachs upgraded PetroChina (NYSE: PTR).

Shares of Greatbatch (NYSE: GB) rose after Banc of America Securities upgraded the medical components maker.

On the downside

Cleveland BioLabs (Nasdaq: CBLI) lost its bid for a $224.7 million defense contract.

Micrel (Nasdaq: MCRL) blamed disappointing sales in Asia for trimming its fourth quarter guidance.

Credit Suisse downgraded Global Payment (NYSE: GPN) .

In the broad market, declining issues outpaced advancers by a margin of nearly 4 to 1 on both the NYSE and on Nasdaq. The Russell 2000 which tracks small cap stocks plunged 17 points to 728.