The U.S. dollar's surge this week has some investors worried that the stock market may be close to hitting a snag.
That concern isn't universal, but it's real for some market players and comes just as all-time highs for major U.S. stock indexes appeared to signal an all-clear for shares, and as corporate earnings are emerging from four straight quarters of declines.
"A strong dollar is going to hurt exporters. You could see that impact on their earnings," said Chris Gaffney, president of EverBank World Markets. "We saw some companies talking about a strong dollar earlier this year, and you could see that rhetoric pick up."