The major U.S. stock indexes plunged in midday trading Thursday on investor concerns that U.S. policy makers are running out of ways to spark the country's struggling economy.

The Dow Jones Industrial Average dropped 3.9 percent. The S&P 500 index fell 3.6 percent. And the NASDAQ slid 3.4 percent.

European stock prices also tumbled sharply.

London's Financial Times index ended down 4.7 percent to close at 5,042. The CAC-40 in Paris dropped 5.3 percent to finish at 2,782. The DAX index in Frankfurt dipped 5 percent to end at 5,164.

In Asia, Tokyo's Nikkei index index lost 2.1 percent (181 points)) to finish at 8,560. Hong Kong's Hang Seng index plunged 4.9 percent to finish the day's trading at 17,912.

The price of gold fell $42.60 to trade at $1,739.70 an ounce.

The dollar fell against the yen but gained against the euro.