Volatility in the currency market is near a record low, and that has led market participants to bulk up on carry trades, which involve borrowing in a currency with low interest rates to invest in another with high rates of return.

But experts warn that those trades can be quite dangerous if volatility kicks up or interest rates suddenly shift.

The low interest rate environment worldwide has investors scouring the globe for decent returns. "Essentially, 'carry' has returned in the pursuit of yield," Anjun Zhou, head of multi-asset research at Mellon Capital Management, told The Wall Street Journal.

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As for the risk of carry trades, "there's a fear that it's based on unsustainable market factors, like low interest rates and volatility in both [foreign exchange] and fixed income," Steven Englander, head of developed-market foreign-exchange strategy at Citigroup, told the paper.

And some experts say it's too late to place carry trades anyway. "If you haven't put on the 'carry' already, it's become a harder trade," Alan Ruskin, head of developed market foreign-exchange strategy at Deutsche Bank, added.

Others agree with Ruskin. "For much of 2014, markets have been dominated by a search for carry and a sense (again) that central banks will keep rates lower for longer," Richard Yetsenga, head of global markets strategy at ANZ, wrote in a recent commentary obtained by CNBC.

"This thematic is being overpriced."

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