Shares of NV Energy soared, last up 23 per cent, after MidAmerican Energy Holdings said it will pay US$5.6 billion for the Nevada utility.
Shares of Facebook gained, last up 5.9 per cent, after broker upgrades. Jefferies & Co and BMO Capital upgraded the stock to buy and outperform, respectively, according to Reuters.
In late afternoon trading in New York, the Dow Jones Industrial Average rose 0.55 per cent, while the Standard & Poor's 500 Index gained 0.70 per cent and the Nasdaq Composite climbed 0.95 per cent.
Europe's benchmark Stoxx 600 Index finished the session with a 0.4 per cent increase from the previous close. The UK's FTSE 100 advanced 0.5 per cent, France's CAC 40 rose 0.6 per cent, while Germany's DAX climbed 0.8 per cent.
The latest data showed an upswing in confidence in the euro zone. An index of executive and consumer sentiment advanced to 89.4 in May, from 88.6 in April, European Commission data showed.
On commodities markets, gold surged 1.5 per cent, while copper ended up about 1 per cent in London. Oil also rose.
"The falling dollar is the only explanation that makes sense for the rebound in oil prices," Michael Lynch, president of Strategic Energy & Economic Research in Winchester, Massachusetts, told Bloomberg.