Wall Street suffered another heavy sell-off yesterday on increasing concerns about global economic recession and weak corporate earning outlook. All major indexes plunged more than 4 percent while the Dow Jones average declined more than 500 points.

Commodity producers led the decline, as investors were concerned about weak global economy will slash demand for commodities. Exxon Mobil and Freeport-McMoRan Copper & Gold Inc. tumbled as crude fell below 67 U.S. dollars a barrel and copper price slid.

Wachovia, which is being bought by Wells Fargo & Co., reported its third straight quarterly loss of 23.9 billion U.S. dollars due to crumbling mortgage markets and write-downs on securities backed by real estate.

Boeing Co. reported profit fell 38 percent after a strike by machinists halted aircraft deliveries.

Merck & Co., the third-largest U.S. drugmaker, said its quarterly profit fell 28 percent and that it would cut more than 10 percent of its work force.

Shares of SanDisk dived after Samsung Electronics Co. walked away from a bid for the company.

In other corporate news, AT&T Inc., the largest U.S. phone company, posted a 5.5 percent gain in third-quarter profit because of strong sales of iPhones.

Apple Inc. posted soaring iPhone sales lifted profit and Chief Executive Officer Steve Jobs said customers will stay loyal in a recession.

The Dow Jones Industrial Average fell 514.45, or 5.69 percent, to 8,519.21, after declining as much as 698 points. The Standard &Poor's 500 index fell 58.27, or 6.10 percent, to 896.78, and the Nasdaq composite index fell 80.93, or 4.77 percent, to 1,615.75.