10 things you need to know before the opening bell

Here is what you need to know.

Senate Republicans come out in furious force against the healthcare bill. Nine Senate Republicans, including Rand Paul of Kentucky and Ted Cruz of Texas, have said they oppose the first iteration of the bill. Only two can vote against the bill in order for it to pass.

The stock market is sending the Fed a crucial message. In a sign that the market believes the economy may not be strong enough to withstand higher rates, companies in sectors that serve as bond proxies - telecom, utility and real estate - were the only ones to see net buying last week, aside from industrials, data compiled by Bank of America Merrill Lynch showed.

Janet Yellen doesn't think we will see another financial crisis in our lifetimes. "Would I say there will never, ever be another financial crisis? You know probably that would be going too far but I do think we're much safer and I hope that it will not be in our lifetimes and I don't believe it will be," Yellen while speaking in London.

The euro hits a one-year high. The single currency hit 1.1388 on Wednesday, a day after upbeat comments from European Central Bank head Mario Draghi. "As the economy continues to recover, a constant policy stance will become more accommodative, and the central bank can accompany the recovery by adjusting the parameters of its policy instruments - not in order to tighten the policy stance, but to keep it broadly unchanged," Draghi said.

Iron ore has its biggest gain in 4 months. The commodity rallied 5.2% in overnight action to $59.70 a tonne, logging its biggest gain since February 13. It's advanced in eight of the past nine sessions, tacking on 11.9% during the streak.

Facebook tops 2 billion users. CEO Mark Zuckerberg made the announcement on his personal Facebook page on Tuesday.

KB Home beats. The homebuilder announced earnings of $0.33 per share on revenue of $1 billion, both better than expected.

Stock markets around the world are mostly lower. Hong Kong's Hang Seng (-0.61%) trailed in Asia and Germany's DAX (-0.48%) lags in Europe. The S&P 500 is set to open up 0.30% near 2,427.

Earnings reports trickle out. General Mills and Monsanto are among the names reporting ahead of the opening bell.

US economic data is light. Pending home sales will be released at 10 a.m. ET. The US 10-year yield is up 4 basis points at 2.24%.