Former FBI Director James Comey testifies at 10 a.m. ET before a Senate panel on the bureau's investigation into whether the Trump campaign had ties to Russia.
But first the European Central Bank holds a rates meeting ahead of the U.S. market open, and traders are watching to see if ECB President Mario Draghi drops any bombshells about the future of the central bank's easing program.
The U.K. also votes in parliamentary elections, called by Prime Minister Theresa May in a bid to win a greater mandate for her Brexit negotiations, but her Conservative party's lead has narrowed dramatically.
"The so-called tinder is there to change things," said Peter Boockvar, chief market analyst
"Of course, the U.K. is relevant depending on what happens with parliament," Boockvar said. "We think May will win. That's a wild card and it matters. Maybe more important to markets will be what Draghi says."
Comey's testimony on his interactions with President Donald Trump was released Wednesday afternoon, ahead of his morning appearance. Stocks moved higher within minutes in a relief trade, and yields broke their recent trend and also moved slightly higher. Bond yields move opposite price, and yields at the long end had been moving to lows not seen since the election. The 10-year was yielding 2.18 percent in afternoon trading, lifting off its earlier level of 2.14 percent.
Comey's appearance before the Senate Intelligence Committee has been seen as key since reports last month indicated that the former FBI director had been asked by Trump to drop his investigation into Michael Flynn, former national security director. Trump fired Comey, and this will be the first time he is being heard from.