Major Asian markets advanced as much as 2 percent, European shares opened modestly higher and crude oil prices cracked $82 a barrel as traders increased their bets on riskier investments. The dollar fell against the euro and rose against the yen.

The US Federal Reserve, following a policy meeting Tuesday, reaffirmed it would keep a key interest rate near zero to help foster economic growth. The central bank said businesses are making more investments and employment was stabilizing.

Its assessment wasn't entirely positive, noting companies were still reluctant to hire and the housing market still weak. But it represented an improvement from the Fed's previous outlook, boosting confidence the economy was headed for sustainable growth.

Then on Wednesday, the Bank of Japan moved to expand easy credit to keep the country's recovery on track and fight deflation, doubling the amount available under its short-term lending program to 20 trillion yen ($221 billion) from 10 trillion yen. It also held its interest rate at a super low 0.1 percent.

“While the bank's move was widely expected, it heartened investors as it shows the Bank of Japan's action and resolve to tackle deflation and support the economy,” said Yutaka Miura, senior strategist at Mizuho Securities Co. Ltd. in Tokyo.

Tokyo's Nikkei 225 stock average rose 125.27 points, or 1.2 percent, to 10,846.98.

Elsewhere, Hong Kong's market jumped 361.56, or 1.7 percent, to 21,384.49 and South Korea's Kospi was higher by 34.85, or 2.1 percent, at 1,682.86.

China's main Shanghai index added 1.9 percent, Australia's market rose 1.2 percent and India's Sensex benchmark climbed 0.8 percent.

In currencies, the dollar rose to 90.63 yen from 90.22 yen. The euro rose to $1.3777 from $1.3769.

Oil prices rose in Asia, with benchmark crude for April delivery up 48 cents at $82.18. The contract added $1.90 overnight.

With Wall Street futures up, US markets were poised to open higher. S&P futures rose 9.2, or 0.8 percent, to 1,159.50.

News from Europe added to Wednesday's upbeat mood. The Standard & Poor's credit rating agency gave its cautious backing Tuesday to the Greek government's attempts to put its fiscal house in order. That helped relieve concerns, at least for now, the country might be hit with a ratings downgrade and default on its massive debts.

Overnight in the US, stocks added to their recent winning streak as the Fed's statement encouraged investors.

The Dow rose 43.83, or 0.4 percent, to 10,685.98. It's up 1.3 percent in the past six days and stands at its highest level since Jan. 19.

The Standard & Poor's 500 index rose 8.95, or 0.8 percent, to 1,159.46, its highest close since October 2008.