YAHOO [BRIEFING.COM]: Woes over the fiscal health of select European nations and some disappointing jobless claims numbers fueled a selling frenzy that culminated in the market's worst single-session percentage loss since April.

Concerns for the fiscal health of Portugal, Greece, and Spain in the wake of some tepid bond auction results stirred early selling interest, which intensified with news that initial jobless claims for the week ended Jan. 30 increased more than expected week-over-week to 480,000. Continuing claims remained steady week-over-week at 4.60 million, but that was still higher than the consensus call for 4.58 million continuing claims.

Disappointment over the headlines led global participants to seek safety in the dollar, which spiked 0.7% to a new six-month high.

Participants wanted little to do with equities, though. In turn, 97% of the issues listed in the S&P 500 logged a loss, which drove the broad-market measure to its lowest close in nearly three months. Meanwhile, the Dow Jones Industrial Average dipped below 10,000 for the first time since early November, but settled just above that psychologically significant line. Cisco (CSCO 23.16, +0.09) was the only Dow component to book a gain, thanks to its better-than-expected earnings and strong guidance.

Visa (V 83.05, -0.47) also exceeded earnings expectations and reaffirmed its outlook for growth, but its shares rolled over from a strong gain in the early going to join peer MasterCard (MA 222.11, -25.47) in the red. MasterCard missed Wall Street's consensus earnings estimate for the latest quarter. The stock was one of the weakest names in the financial sector, which fell 4.2%, worse than any other major sector.

Natural resource plays had been among the poorest performers for most of the session. Their losses were linked to broader market weakness and sharp losses in the commodity complex, which dragged down the CRB Commodity Index to a new three-month low and a 2.6% loss for the session.

Weakness among commodities was broad based as oil prices plummeted 5.0% to $73.14 per barrel. Prices haven't fallen by such a sharp percentage since summer. Meanwhile, gold prices were pushed 4.3% lower to $1064 per ounce -- December marked the last time that gold fell by more than 4%.

Volatility spiked amid this session's sell-off. That resulted in a near 21% rise in the Volatility Index, which is often dubbed the VIX, or more ominously the Fear Index.

Retailers mostly made up the handful of names to book gains in the broader market. That was largely the result of several upbeat same-store sales reports for January. Still, retailers fell a collective 2.3%.

As if the breadth of this session's slide wasn't telling enough of conviction, trading volume on the NYSE came close to 1.5 billion shares, which is well above its 50-day and 200-day moving average.

While this session's sell-off will weaken sentiment in the broader market, participants still have yet to see the latest nonfarm payrolls report, which often brings volatility all on its own. The nonfarm payrolls report for January is scheduled to be released Friday morning at 8:30 ET.

Advancing Sectors: (None)
Declining Sectors: Financials (-4.2%), Energy (-3.9%), Materials (-3.8%), Industrials (-3.1%), Tech (-2.9%), Consumer Discretionary (-2.9%), Utilities (-2.6%), Health Care (-2.6%), Telecom (-2.4%), Consumer Staples (-2.3%)DJ30 -268.37 NASDAQ -65.48 NQ100 -2.9% R2K -3.4% SP400 -3.2% SP500 -34.17 NASDAQ Adv/Vol/Dec 366/2.78 bln/2319 NYSE Adv/Vol/Dec 272/1.48 bln/2842