The European debt crisis has caused Moody's Investors Service Inc. to downgrade the credit rating of Germany, the Netherlands and Luxembourg. 

Moody's downgraded the three countries from Aaa stable to Aaa negative. A full downgrade is still possible, CNNMoney reported.

Germany has often been viewed as a leader in financial stability in Europe, according to Bloomberg, but troubles in Greece, Spain and Italy have drawn concern from the financial ratings agency.

Because Germany is the largest economy in the eurozone and its banks have been bailing out countries, Moody's said Germany could get hit harder than other European countries if the debt crisis continues.

The U.S. stock market reacted negatively this morning to the news in Europe.