U.S. stocks turned lower on Wednesday, following the S&P 500's biggest jump in a year, as investors considered the fatal shooting of a soldier in Ottawa, reports of gunfire in the halls of Canada's Parliament and oil falling to a more-than two-year low.
A military guard died after getting shot at the National War Memorial in Ottawa, with multiple rounds then reportedly fired at the adjacent Parliament building. The gunfire followed increased worry about terrorist attacks in Canada, where a radical jihadist ran over two soldiers in a suburb of Montreal on Monday, killing one.
"It hits close to home, and with everything going on in the world, perhaps it's a contributor," Stephen Carl, head equity trader at the Williams Capital Group, said of the situation in Canada's capital, where lawmakers reportedly had barricaded themselves in their offices.
"You don't know what going on there is Ottawa; as we've seen over the last couple of weeks, people buy protection on news or perceived news out there," JJ Kinahan, chief strategist at TD Ameritrade, said of the CBOE Volatility Index, a measure of investor uncertainty, which jumped 11 percent to 17.87.
Equities began to ease gains as the price of oil turned lower after data had U.S. inventories rising more than expected.
"For the market to regain footing, we need the price of oil to stabilize," said Anastasia Amoroso, global market strategist at J.P. Morgan Funds.
Boeing declined after the plane manufacturer reported quarterly results, as analysts questioned the costs of its 787 Dreamliner; Yahoo rose after the search engine reported quarterly results that topped estimates.