YAHOO: Global economic concerns and earnings concerns sank stocks for the second straight session.

The S&P 500 spent the entire session in negative territory, falling 6.1% to its lowest closing level in five years. Weakness was broad-based with 478 of the S&P 500 components posting a loss, although volume was on the light side when considering the scope of this session's move.

Similar to Tuesday, the majority of companies (56%) reported better-than-expected earnings for the latest quarter, but outlooks were negative. Of the companies that issued earnings guidance with their quarterly reports, 39% were negative, 29% were in-line, 24% were mixed and only 7% were positive.

A few of the more widely-held names that topped earnings estimates include Apple (AAPL 96.57, +5.08), McDonald's (MCD 54.46, -0.67), Merck (MRK 28.02, -6.51) and Phillip Morris International (PM 40.94, -1.22). Of note, Merck plans to cut 7,200 jobs, or 13% of its workforce.

Yahoo! (YHOO 12.39, +0.32) reported a profit drop that met estimates, and said it plans to lay off 10%, or 1,500, of its workforce.

AT&T (T 23.93, -1.80) and Boeing (BA 43.03, -3.37) are two of the bigger names that missed earnings estimates.

All ten of the economic sectors posted a loss, ranging from -10.4% (energy) and -3.8% (consumer staples)

A sharp drop in crude prices in conjunction with disappointing earnings from ConocoPhillips (COP 49.06, -4.90) and Baker Hughes (BHI 30.43, -8.52) caused a 10.4%decline in energy stocks.

On related note, the material sector fell 8.3% as copper prices plunged 9.7%.

The defensive-oriented consumer staples sector outperformed on a relative basis with a decline of 3.8%.

The dollar rallied for the third straight session, with today's gains fueled by weakness in overseas markets and Bank of England Governor King saying that a U.K. recession seems likely -- The DJ World Index excluding US dropped 6.8%.

The strength in the dollar and global economic fears sparked a broad-based sell-off in commodities (-4.5%). Crude oil prices plunged 7.4% to $66.84, with selling interest compounded by the fourth straight weekly increase in inventory levels.

As stocks and commodities faltered, the long end of the Treasury curve rallied as investors sought safety. The benchmark 10-year note climbed more than a point to push its yield down to 3.60%. DJ30 -514.45 NASDAQ -80.93 NQ100 -3.6% R2K -5.9% SP400 -5.4% SP500 -58.27 NASDAQ Adv/Vol/Dec 353/2.57 bln/2391 NYSE Adv/Vol/Dec 461/1.56 bln/2657