By early 2007, it was estimated that some US$1 trillion may have been staked on the yen carry trade.

The risk in carry trading is that foreign exchange rates may change to the effect that the investor would have to pay back more expensive currency with less valuable currency.

In theory, according to uncovered interest rate parity, carry trades should not yield a predictable profit because the difference in interest rates between two countries should equal the rate at which investors expect the low-interest-rate currency to rise against the high-interest-rate one. However, carry trades weaken the currency that is borrowed, because investors sell the borrowed money by converting it to other currencies.

By early year 2007, it was estimated that some US$1 trillion may have been staked on the yen carry trade.

Since the mid-90's, the Bank of Japan has set Japanese interest rates at very low levels making it profitable to borrow Japanese yen to fund activities in other currencies. These activities include subprime lending in the USA, and funding of emerging markets, especially BRIC countries and resource rich countries.

The trade largely collapsed in 2008 particularly in regards to the yen.

The 2008–2011 Icelandic financial crisis has among its origins the undisciplined use of the carry trade.

Particular attention has been focused on the use of Euro denominated loans to purchase homes and other assets within Iceland. Most of these loans defaulted when the relative value of the Icelandic currency depreciated dramatically, causing loan payment to be unaffordable. This was also true in a number of Eastern European countries.

The US dollar and the yen have been the currencies most heavily used in carry trade transactions since the 1990s. There is some substantial mathematical evidence in macroeconomics that larger economies have more immunity to the disruptive aspects of the carry trade mainly due to the sheer quantity of their existing currency compared to the limited amount used for FOREX carry trades, but the collapse of the carry trade in 2008 is often blamed within Japan for a rapid appreciation of the yen.

As a currency appreciates there is pressure to cover any debts in that currency by converting foreign assets into that currency, so this can be an accelerating effect in currency valuation changes. When a large swing occurs, this can cause a carry reversal. The timing of the carry reversal in 2008 contributed substantially to the credit crunch which caused the 2008 global financial crisis, though relative size of impact of the carry trade with other factors is debatable.

A similar rapid appreciation of the US dollar occurred at the same time, and the carry trade is rarely discussed as a factor for this appreciation.