YAHOO [BRIEFING.COM]: Another round of highly volatile trade brought broad-based losses, but this session's slide wasn't as bad as the prior session's selloff. Still, many market participants seem to have grown increasingly skittish.

The prior session's 2.4% slide was the worst single-session percentage loss since February, but stocks failed to quickly snap back as they had so many other times. Instead, sellers stepped right back in to drop the S&P 500 another 1% in the early going. The pressure pushed the benchmark index well below its 50-day moving average, which hadn't been broken for two months.

Early weakness was partly owed to persistent concerns about the fiscal health of Greece and the rest of the PIIGS contingent, which includes Portugal, Ireland, Italy, and Spain. Moody's reminded investors of their risk with news that Portugal's debt has been placed on review for possible downgrade.

Lost support for the euro and an interest in safety drove the U.S. dollar sharply higher once again. The greenback set a new 11-month high against a collection of competing currencies before it eased back. Still, it closed with a 1.0% gain and is now up 8.0% year-to-date.

With many global participants turning away from riskier assets and riskier markets the Dow Jones World Index fell 1.3%. The World Index dropped 1.7% when excluding the U.S., given that U.S. stocks were able to trim losses.

The S&P 500 had been down as much as 1.3% at its session low, but support from a technical trend line through 1158 triggered a rebound that took stocks all the way to positive territory. The gain proved unsustainable and stocks drifted lower into the close, though.

Of the major sectors, consumer staples (+0.3%) and health care (+0.2%) were the only two that managed to stage gains. Telecom limited its loss to just 0.1%.

Some of the worst losses were found in the energy sector, which was weighed down by broader market weakness and another sharp drop in oil prices. Crude oil prices had dropped 4% in the prior session and then surrendered 3.3% this session. Oil prices now stand at $79.97 per barrel, below the $80 per barrel mark for the first time in more than one month. The latest bout of selling was exacerbated by a larger-than-expected build in weekly oil inventories.

Financials had offered some midsession support to the broader market by making a swing from a near 2% loss to a near 1% gain. However, the sector succumbed to pressure as sellers redoubled their efforts; it finished with a 0.5% loss.

Volatility spiked once again. Amid early selling the Volatility Index spiked roughly 14% to a new three-month high, but it pulled back to settle nearly 5% higher.

Treasuries garnered support amid the highly volatile action. In fact, strong gains in the benchmark 10-year Note dropped its yield below 3.50% for the first time this year. The gain moderated so that the Note's yield climbed to 3.55% into the close.

Heightened participation helped trading volume on the NYSE hit 1.5 billion shares for the second straight session. That's the first time this year that volume has hit 1.5 billion shares on back-to-back sessions.

Economic data has done little for trade for the second straight session, but that's mostly due to a lack of surprise as the April ISM Service Index came in at 55.4, which was just below the 56.0 that had been widely forecast. The ADP Employment Report for April showed a slightly greater-than-expected 32,000 private payroll additions.

The CRB Commodity Index gave up 1.3% this session. That leaves it down 3.5% week-to-date.

Oil has been one of the weakest components for the CRB. Crude oil prices dropped 4% in the prior session and surrendered another 3.3% this time around. Oil prices now stand at $79.97 per barrel, below the $80 per barrel mark for the first time in more than one month. Their weakness this session was exacerbated by a larger-than-expected build in weekly oil inventories.

Natural gas prices surrendered a more modest 0.7% this session. Contracts closed at $3.98 per MMBtu.

Precious metals were mixed. Gold prices oscillated for most of the session, but were able to close with a 0.5% gain at $1175 per ounce. Silver settled a sharp 1.7% lower at $17.53 per ounce.

Advancing Sectors: Consumer Staples (+0.3%), Health Care (+0.2%)
Declining Sectors: Energy (-1.5%), Industrials (-1.5%), Consumer Discretionary (-1.4%), Materials (-0.8%), Utilities (-0.7%), Tech (-0.6%), Financials (-0.5%), Telecom (-0.1%) DJ30 -59.94 NASDAQ -21.96 NQ100 -0.5% R2K -1.6% SP400 -1.1% SP500 -7.73 NASDAQ Adv/Vol/Dec 675/2.94 bln/2039 NYSE Adv/Vol/Dec 625/1.50 bln/2461