NEW YORK » Wall Street tumbled again yesterday as investors worried that the global economy is poised to weaken even as parts of the credit market slowly show signs of recovery. The major indexes fell more than 4 percent, including the Dow Jones industrial average, which finished off its lows with a loss of 514 points.

The Standard & Poor's 500 index was the worst performer among the major indexes with a 6.1 percent slide that left it at its lowest level since April 2003.

Corporate profit forecasts, a jump in the dollar and falling oil prices signaled investors are fearful that an economic slowdown will sweep the globe even if lending begins to approach more normal levels.

The dollar hit multiyear highs against several other major currencies, weighing on commodity prices. That hurt raw materials and energy companies, while giving a boost to airlines. Technology shares fared better than the broader market following quarterly reports from Apple Inc. and Yahoo Inc. Apple rose after the company reported a 26 percent increase in its fiscal fourth-quarter earnings. The stock rose $5.38, or 5.9 percent, to $98.87. Yahoo reported a 64 percent drop in third-quarter profits but said it would cut at least 1,500 jobs, cost-cutting that appeared to please investors. The shares rose 32 cents, or 2.7 percent, to $12.39.

While reduced strains in global credit markets have eased some investors' nervousness about the economy, market anxiety remains as hundreds of companies this week report third-quarter results and issue somewhat murky forecasts that are stirring unease about the economic bumps that may lay ahead.

Wachovia Corp., which is being bought by Wells Fargo & Co., reported that it swung to a $24 billion loss in the third quarter while the drugmaker Merck & Co. said its quarterly profit fell 28 percent and that it would cut more than 10 percent of its work force.

The Dow fell 514.45, or 5.69 percent, to 8,519.21, after being down as much as 698 points in the final half hour of trading. The Standard & Poor's 500 index lost 58.27, or 6.10 percent, to 896.78, its lowest close since it finished at 892 on April 21, 2003. The Nasdaq composite index fell 80.93, or 4.77 percent, to 1,615.75. The Russell 2000 index of smaller companies fell 28.68, or 5.40 percent, to 501.97.

Credit markets showed im-provement after virtually freezing up in the past month. The London Interbank Offered Rate, or Libor, on three-month loans in dollars fell to 3.54 percent from 3.83 percent, dropping for an eighth straight day.

The greenback rose against currencies like the British pound and the euro as investors worried about sluggishness in overseas economies.

Light, sweet crude fell $5.43 to $66.75 a barrel on the New York Mercantile Exchange, after falling as low as $66.20.