The markets opened sharply lower with the Dow plummeting 174 points to 15,163 despite a rise in homebuilder confidence as investors fretted over the impending Federal Reserve tapering. Nasdaq plunged 48 points to 3621.

On the upside

Maxim Integrated Products will acquire Volterra Semiconductor (Nasdaq: VLTR) in a deal valued at approximately $605 million.

Lazard Capital analyst William Tanner lifted his price target on Novavax (NYSE: NVAX). 

Biolase (Nasdaq: CCCR) lowered its offering from $30 million to $5 million.

On the downside

Himax Technologies (Nasdaq: HIMX) reported higher second quarter earnings but revenue fell short of expectations and the company forecast current quarter revenue below estimates.

Renren (NYSE: RENN) narrowed losses for the second quarter but revenue growth slowed.

Profit taking sank shares of MannKind (Nasdaq: MNKD).  

In the broad market, declining issues outpaced advancers by a margin of nearly 7 to 1 on the NYSE and by more than 4 to 1 on Nasdaq. The broader S&P 500 dropped 19 points to 1666.