U.S. stocks plunged for a second day on Friday, in the worst week for the S&P 500 in nearly five years, as tightening credit conditions led to concerns that takeovers would slow.

Losses accelerated in the final minutes of trading, taking the Dow industrials down more than 200 points, a day after an equities sell-off that wiped out more than $300 billion in the value off the S&P 500.

Investors fear increasing deterioration in credit markets would hurt chances for more corporate buyouts and dry up funding, and that losses in the subprime mortgage market may spill over into the broader economy.

A nearly 3 percent rise in oil prices to their second-highest settlement on record added to worries about the economy. Energy company shares, however, led decliners on the S&P 500. Exxon Mobil Corp., which reported worse-than-expected results this week, dropped 3 percent.

The Dow Jones industrial average fell 208.10 points, or 1.54 percent, to end at 13,265.47. The Standard & Poor's 500 Index was down 23.71 points, or 1.60 percent, at 1,458.95. The Nasdaq Composite Index was down 37.10 points, or 1.43 percent, at 2,562.24.

For the week, the Dow fell 4.2 percent, the S&P dropped 4.9 percent and the Nasdaq declined 4.7 percent.

The S&P suffered its worst one-week percentage drop since September 2002, while the Dow fell 585 points on the week, the biggest weekly point drop since July 2002.

Selling in financial shares also weighed on the market, with shares of Citigroup Inc. (C.N) among the biggest decliners on the S&P 500. Citigroup was down 1.8 percent at $46.97.