The Japanese yen posted a second week of gains as concerns the debt problems in the US and Europe made the currency more appealing as a safe haven.

The US dollar erased its gains today and posted the biggest weekly decline in three months after Standard & Poor’s warned that it may cut the US credit rating as the US lawmakers can’t agree on the nation’s debt ceiling.

The Canadian dollar advanced today against all 16 most-traded currencies after eight banks in the European Union failed the stress tests, increasing concerns about the EU financial system.

The Australian dollar fell today, heading for the second weekly loss against the US dollar and the Japanese yen, as stocks and commodities declined on concerns that problems in the US and Europe will have negative impact on the global growth.

Asian currencies, including the Indian rupee, fell today on concerns that the debt issues in the US and Europe will threaten the global economic growth.

The US dollar regained its strength today after Federal Reserve Chairman Ben Bernanke signaled today that there won’t be a third round of quantitative easing.

The Swiss franc touched a record versus the US dollar, the euro and the Great Britain pound today after Fitch Ratings downgraded Greece’s credit rating. The currency erased gains on the speculation that the Federal Reserve won’t continue its quantitative easing program.

The New Zealand dollar advanced against all 16 most-traded currencies, touching the all-time high versus the US dollar and reaching the highest level since 2005 against the euro, as growth of the New Zealand economy beat estimates.

The US dollar slid today, falling against the euro for the second day, as Moody’s Investor Service put the US credit rating on review for the first time since 1995.

The US dollar fell today against all most-traded currencies after Federal Reserve Chairman Ben S. Bernanke suggested that the Fed is ready to continue the quantitative easing if necessity for more stimulus would arise.