Investors this morning poured cold water on fears that the so-called carry trade, where low-yielding currencies are borrowed to buy higher-yielding ones, is under threat after the Bank of Japan said it would raise interest rates and the Swiss National Bank said it could follow suit.

Investors have been borrowing in Japanese yen and Swiss francs, which have the lowest interest rates in the developed world, and investing in countries where rates are higher. That has put downward pressure on the yen and Swiss franc and made other currencies artificially strong.