US pre-open: Investors standing by for Yellen's testimony

US futures had risen in anticipation of Janet Yellen’s testimony to the House Financial Services Committee on Wednesday.

The Dow Jones Industrial Average was set to open up 138 points, while the S&P 500 and the Nasdaq were expected to start the session 20 and 63 points higher respectively.

Key data out after the market opens includes oil and gas inventories at 1530 GMT, just after Yellen begins her semi-annual monetary policy report at 1500 GMT.

Japan stocks hit lowest level since 2014

Stocks in Japan hit their lowest levels since 2014 on Wednesday, as investors in the region remained worried about the Federal Reserve's interest rate plans, and the general health of the global banking sector.

At one point during trading, Tokyo managed to negate all the gains it had made since the Bank of Japan embarked on a controversial easing policy in October 2014.

Asian markets appeared to continue their selloff as a response to concerns that the global banking sector was running out of options to support growth.

"The [January] BOJ decision is backfiring. There has been a lot of stimulus by the central bank ... its tools are increasingly looking limited", said Aberdeen Investment Management assistant investment manager Kei Okamura.

There was also concern that corporate profits were relying on the exchange rate to drive up their numbers since Prime Minister Shinzo Abe took power.

"There are some concerns that if that starts to reverse, we could go back to square one", said Fukoku Mutual Life Insurance general manager of equities Ichiro Yamada.

Investors appeared to believe Asian markets were yet to reach the bottom of the trough, with low crude prices also creating bad debt in the banking system.

"Until turmoil eases overseas, it is hard to expect a market recovery," said Ichiyoshi Investment Management chief fund manager Mitsushige Akino.

European stocks racked up solid gains on Wednesday, with banks surging ahead following heavy losses in the previous session,as investors looked to Yellen’s testimony before Congress.

Oil prices had rebounded slightly, with West Texas Intermediate up 2.11% to $28.53 a barrel and Brent rising 2.21% to $30.99.

The dollar was up 0.34% against the euro, but had dropped 0.54% against the pound and 0.10% against the yen. Spot gold was down 0.42% to $1,184.17.

In company news, SolarCity Corp. shares plunged over 30% after it said late on Tuesday that it will continue to fall short of its installation goals.

Despite positive earnings due to the success of Star Wars, Disney shares were down 4% on concerns about cable sports network ESPN.