Wall Street awaits Yellen; Time Warner stock soars

U.S. stock index futures pointed to a higher open on Wall Street on Wednesday, ahead of U.S. Federal Reserve Chair Janet Yellen's second day of congressional testimony.

Stock futures retained their gains as the government reported producer prices rose0.4 percent in June, versus expectations of a 0.2 percent increase.

Time Warner garnered significant interest in pre-market trade, after CNBC reported it had rejected a $80 billion takeover bid by 21st Century Fox, which confirmed making an offer for Time Warner, but also said the companies were not currently in discussions.

Shares of Time Warner shot up nearly 17 percent on the report in early New York trading.

Time Warner rejects $80B offer from 21st Century Fox

Bank of America reported second-quarter profit that beat estimates, as did BlackRock.

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Bank of America quarterly profit drops 43 percent

U.S. Bancorp reported net income of $1.50 billion for the second quarter, or 78 cents per diluted common share. This compared with net income of $1.48 billion in the same period a year before.

Northern Trust posted second-quarter earnings per common share of 75 cents and net income of $181.9 million.

EBay and Yum! Brands will report after U.S. markets close.

Yellen in focus

After the earnings flurry, attention will move to Yellen's testimony in front of U.S. lawmakers.

"It should be pretty identical to yesterday, so no new surprises are expected. The Q&A could be worth watching though," said Deutsche Bank's Jim Reid in a morning research note.

On Tuesday, Yellen reiterated that the Fed's loose monetary policy remained appropriate as the economic recovery was still incomplete.

She also expressed concerns about stretched valuations in equity markets, especially the social media and biotech sector. This saw Wall Street finish mostly lower overnight, despite better-than-expected second-quarter earnings from JPMorgan and Goldman Sachs.

In other news, Dallas Fed President Richard Fisher will speak on monetary policy on Wednesday. He has expressed concern over market complacency and low volatility, and may do so again.