Any of three big events today, each with significant risk, could rattle complacent markets, where bonds and stocks have been making the unusual move of going higher together.
U.K. voters have already gone to the polls for parliamentary elections, while the ECB will hold a rates meeting ahead of the market open.
In the U.S., former FBI Director James Comey will testify in one of the most-anticipated congressional hearings in years.
Now read: Data out of East Asia »
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