Japanese yen banknotes of various denominations are arranged for a photograph in Tokyo, Japan, on July 22, 2015.

The safe-haven yen and Swiss franc surged on Monday, as risk appetite plummeted after a 30% crash in oil prices and tumbling stock markets panicked investors and sent currency prices swinging wildly.

Investors were also alarmed after U.S. Treasury yields declined to record lows, with the benchmark 10-year yield falling below 40 basis points and the entire yield curve below 1% for the first time ever.