The Japanese yen and its exchange traded fund (ETF) have been on a tear lately, but not everyone is excited about the currency’s rapid ascent.

The Group of Seven countries issued a statement saying they’re concerned about the yen’s volatility, reports Martin Crutsinger for the Associated Press. The yen is at a 13-year high against the dollar, which has heightened concerns in Japan that its exports will be harmed.

The G-7 reaffirmed its shared interest in a strong financial system, and is vowing to continue to watch the markets. The group’s pledge could signal a possibility of a joint intervention in currency markets, in which governments would buy and sell currencies in order to influence their values.

History suggests the United States would sit this one out, as the Bush administration has never participated in such an intervention.

Why is a strong yen such a big deal? Paul R. LaMonica for CNN Money reports that since Japan is such a big exporter of goods, a robust yen hurts profits, which will then hurt the country’s stock market. That, in turn, could have a ripple effect on exchanges in the United States and Europe.

One economist says that the Nikkei is heavily influenced by manufacturers and exporters. Already, Toyota is feeling the pinch from a weakened global economy and stronger yen. Financial firms are straining, too.

The CurrencyShares Japanese Yen (FXY) is up 17.3% year-to-date, and up 11.7% in the last month.

Read the disclosure, as Tom Lydon is a board member of Rydex Funds.

Tags: Asia, Currency ETFs, Japan, Japanese Yen