The continued slowdown of the U.S. economy, coupled with the impending resolution of the Greek debt crisis, boosted exchange rates for the dollar and yen this week. Currency traders, fearing that the slump would have global effects, opted to stay safe by buying up currencies they considered “safe havens.”

According to a report by Reuters yesterday, the International Monetary Fund (IMF), the European Central Bank (ECB), and the European Union (EU) announced they cannot release any more funds for Greece’s bailout program until the country’s under-financing problem is corrected.

This caused the euro to go down, dragging commodity currencies along with it. It also caused the Japanese yen to rise to 79.693 per dollar, its highest level in more than a month. Leveraged investments rose as buyers borrowed money in a rush to buy the currency to shelter high-yield assets in the event of a global economic slowdown.

The same circumstances also helped the U.S. dollar gain ground against other high-yielding currencies, including the euro and the Australian dollar, according to traders. Low interest rates in the U.S. make their currency a popular tool for funding, as is the case with the yen.

Traders have been more sensitive to global growth concerns since the global financial crisis, which cost investors millions across the board. According to market analyst Joe Manimbo of Travelex Global Business Payments, a Washington-based company, such events are likely to take root in the U.S., and traders’ concerns have made the yen and the dollar popular for those seeking secure investments.

Recent events, such as the drop of hiring in May (following a short hiring surge in Silicon Valley earlier) and Fed Chairman Ben Bernanke’s announcement that economic recovery is still uncertain, also contributed to investors’ increased caution.

The yen showed particularly strong growth against the dollar and the euro, with the former hitting its lowest point in a month on the EBS platform. This is said to have triggered “auto-traders” to sell their currencies after the dollar fell below 80 yen. If the numbers go below 79.50, more of these traders will automatically sell, experts said.

Fitch Ratings warned that present changes can lower the U.S. credit rating, especially if the government cannot increase its borrowing limit and meet payments. However, the Paris-based international rating agency said the events put attention on the country’s growing financial problems, which could affect the dollar for years to come.