Falling consumer confidence sent the markets tumbling during the midday with the Dow plunging 145 points to 12,708. Nasdaq dropped 24 points to 2464.

On the upside

Employers Holdings (Nasdaq: EIG) will pay approximately $196.5 million to acquire AmCOMP (Nasdaq: AMCP).

The Securities and Exchange Commission ended its informal inquiry into Usana Health Sciences' (Nasdaq: USNA) marketing practices and will take no action against the company.

Blackstone Group (NYSE: BX) may pay up to $930 million to purchase GSO Capital Partners.

On the downside

Cadence Pharmaceuticals (Nasdaq: CADX) reported that its intravenous pain treatment Acetavance failed a late stage clinical trial.

Opnext (Nasdaq: OPXT) warned that third quarter sales will fall short of expectations as demand declined.

RF Micro Devices (Nasdaq: RFMD) blamed weaker than expected demand for lowering its third quarter outlook.

In the broad market, declining issues outpaced advancers by a margin of nearly 5 to 4 on the NYSE and by more than 5 to 3 on Nasdaq. The Russell 2000 which tracks small cap stocks lost 4 points to 716.