Standard & Poor's downgraded its outlook for the United States to negative sending the markets tumbling to a sharply lower open with the Dow plummeting 193 points to 12,147. Nasdaq plunged 48 points to 2716.
On the upside
Amarin (Nasdaq: AMRN) reported positive results from a Phase 3 ANCHOR trial of its AMR101.
Identive Group (Nasdaq: INVE) unit SCM Microsystems will provide 10,000 eHealth terminals for Germany's electronic health card program.
Goldman Sachs analyst Mark Wienkes upgraded A123 (Nasdaq: AONE) to a Buy rating.
On the downside
Hecla Mining (NYSE: HL) halted all mining operations to rescue a missing miner at its Lucky Friday mine in Northern Idaho that occured after a localized fall of ground on April 15.
Retreating silver prices weighed down shares of First Majestic Silver (NYSE: AG).
In the broad market, declining issues outpaced advancers by a margin of more than 7 to 1 on the NYSE and by more than 6 to 1 on Nasdaq. The Russell 2000 which tracks small cap stocks tumbled 14 points to 820.