Reports that China's central bank increased its stimulus measures boosted the markets to a sharply higher close with the Dow soaring 100 points to 17,131. Nasdaq gained 33 points to 4,552.

On the upside

Speculation that a new government will be elected in October lifted shares of Petrobas (NYSE: PBR). President Dilma Rousseff and his administration has been plagued by accusations of bribery.

Micron Technology (Nasdaq: MU) introduced its next generation M600 solid-state drive.

MKM Partners affirmed its Buy rating on Twitter (NYSE: TWTR).

On the downside

Odyssey Marine Exploration (Nasdaq: OMEX) completed the current recovery phase of its operations on the SS Central America shipwreck.

Net Element (Nasdaq: NETE) extended its losses.

Advanced Micro Devices (NYSE: AMD) collaborated with Canonical to deploy an OpenStack private cloud but the stock price fell.

In the broad market, advancing issues outpaced decliners by a margin of more than 5 to 3 on the NYSE and by more than 10 to 9 on Nasdaq. The broader S&P 500 climbed 14 points to 1998. Bitcoin lost $11 to $461.