Concerns about the Chinese banking system sent the markets tumbling to a sharply lower open with the Dow slumping 217 points to 14,581. Nasdaq plummeted 51 points to 3305.
On the upside
Tenet Healthcare (NYSE: THC) will pay a premium of approximately $1.73 billion to acquire Vanguard Health Systems (NYSE: VHS).
STEC (Nasdaq: STEC) will be acquired by Western Digital (Nasdaq: WDC) in an all cash deal of approximately $340 million.
Isis Pharmaceuticals (Nasdaq: ISIS) reported positive results from a Phase 2 study of its high triglyceride and type 2 diabetes treatment ISIS-APOIII Rx.
On the downside
Investors locked in profits on Cytokinetics (Nasdaq: CYTK).
Andy Tian, the head of Zynga's (Nasdaq: ZNGA) China operations, will depart the company at the end of June.
Deutsche Bank downgraded Allergan (NYSE: AGN) from a Buy rating to a Hold rating and lowered its price target from $113 to $98.
In the broad market, declining issues outpaced advancers by a margin of more than 13 to 1 on the NYSE by more than 7 to 1 on Nasdaq. The broader S&P 500 index plunged 26 points to 1566.