U.S. and European stock markets nosedived on Wednesday just one day after seeing sharp rallies.

Stock markets in Europe saw a strong start at the beginning of the day, but plunged more than five percent after rumors emerged that France’s AAA credit rating could be downgraded.

The world’s top three major ratings agencies, including Moody’s, rushed to dismiss such rumors, stressing that they have no plans to downgrade France. However, concerns over a possible downgrade led to the five percent drop in most markets in Europe, including France, Italy and Germany.

Such a fall in European stocks led the Dow Jones Industrial Average to close down 520 points, or four-point-six percent, on Wednesday.