The Dow Jones industrial average dropped 700 points in early trading today, then bounced into positive numbers before declining by midmorning.

In short, it was the start of another wild ride on Wall Street sparked by early buying of bargain-priced stocks and followed by a bumpy sell off.

By 10 a.m. Iowa time, most U.S. stocks had fallen as the escalating credit crisis spurred concern that more companies would fail. By 11 a.m., the Dow was down 432.89 to 8,146.30. Of local interest, shares of West Bancorporation Inc. were trading at $9.66, up 58 cents. At that same time, shares of Principal Financial Group Inc. dropped below $16, trading at $15.66, but had climbed to $16.47 within the next 22 minutes.

Benchmark indexes pared declines as regional banks rallied on speculation they’ll capture more market share, Bloomberg reported.

Wachovia Corp., Fifth Third Bancorp and Regions Financial Corp. climbed more than 15 percent, helping the Standard & Poor’s 500 index pare a slump of as much 7.7 percent.

The S&P 500 had declined 7.43 points, or 0.8 percent, to 902.49 at 9:17 a.m. in Iowa, extending its weekly plunge to 18 percent. The Dow Jones industrial average slipped 77.02 points, or 0.9 percent, to 8,502.17, paring a 697 point drop. The Nasdaq composite index was up 0.1 percent to 1,646.83.

The S&P 500 has fallen for eight straight days, its longest losing streak since 1996. The declines pushed both the S&P 500 and Dow average down more than 40 percent from their peaks last October and set them on course for their worst yearly returns since the Great Depression.

The rout left the S&P 500 valued at 17 times the reported earnings of its constituent companies, its cheapest level in more than a year.

Credit markets stayed frozen as the cost of borrowing in dollars in London for three months rose for a fourth consecutive day. The London interbank offered rate, or Libor, that banks charge each other for such loans climbed 7 basis points to 4.82 percent today, the British Bankers’ Association said.

More than $20 trillion has been wiped off equity markets in the last 12 months as the financial crisis that started with nonperforming U.S. subprime loans spread to economies globally.

The New York Times reported that at the open today of European markets the Dow Jones Euro Stoxx 50 index was down 8 percent. The FTSE 100 index in London was down 6.2 percent, the CAC-40 in Paris was down 7.2 percent and the DAX in Frankfurt was down 7.9 percent.

Stock markets in Asia plunged on Friday as investor sentiment was battered by the overnight rout on Wall Street, by confirmation that Singapore had slid into recession and by news of a financial-sector bankruptcy in Japan.

In Tokyo, the Nikkei 225 index — already shaken by a nearly 10 percent drop on Wednesday — slumped another 9.6 percent on Friday, closing at 8,276.43.