YAHOO [BRIEFING.COM]: Threats of tighter monetary policy in China and increased bank regulation combined with a sell-the-news mentality to drop the stock market for its worst single-session percentage loss in nearly 12 weeks.

Stocks had already tumbled significantly in the previous session, but sellers were back at it after China reported stronger-than-expected fourth quarter GDP growth and a sharper-than-expected spike in inflation, which renewed concern that tighter monetary policy may be in the offing. Tighter policy in China would presumably crimp the country's growth and slow the global economic rebound.

Such a consideration has weighed on both stocks and commodities for two straight sessions. That has had a doubly negative impact on materials stocks, which sank to a 4.3% loss in their latest showing.

Meanwhile, energy stocks dropped 2.0% as oil prices were pushed to a near one-month low of $75.66 per barrel before they finished pit trade with a 2.1% loss at $76.08 per barrel. Price erosion came in the face of a surprise inventory draw of 4.7 million barrels during the week that ended Jan. 15.

Financials were forced a sharp 3.0% lower. President Obama stirred concern for financials with the announcement that plans are being put together to ensure that no bank will own, invest in or sponsor a hedge fund or a private equity fund, or proprietary trading operations unrelated to serving customers for its own profit. Further, the proposal will place broader limits on the excessive growth of the market share of liabilities at the largest financial firms. Though details of any such plan will change as it moves through the legislative process, the idea behind such a plan is a negative for big financial institutions.

The announcement seemed to exacerbate weakness in Goldman Sachs (GS 160.87, -6.92), which had already succumbed to profit-taking by participants who believed that its better-than-expected earnings of $8.20 per share had already been priced into the stock. The company's in-line revenue results also dulled the glimmer of its upside earnings surprise.

However, regional banks were able to garner support and put together a 0.8% gain. They were actually up nearly 3% at their session high as investors acted on knowledge that regional lenders won't be as restricted by Obama's regulatory proposals as their larger competitors. Regional banks were generally an exception to the recent sell-the-news trend and, as a result, were helped by a handful of better-than-expected quarterly reports.

Another exception to the recent sell-the-news trend was eBay (EBAY 24.13, +1.90). Its upside earnings surprise helped it net its best single session advance by percent in six months. That was even more impressive given the scope of losses in the broader market this session.

Volatility surged amid this session's slide. The Volatility Index closed some 19% higher in its sharpest move in two months.

Trading volume topped 1.5 billion shares on the NYSE this session. That's well above recent averages and suggestive of strong underlying conviction.

As an aside, initial weekly payrolls continue to come in at elevated levels. Initial claims for the week ended Jan. 16 totaled 482,000, which was more than the 440,000 initial claims that had been expected. It was also up from the prior week's 446,000 initial claims tally.

Meanwhile, continuing claims came in at 4.60 million, which matched the consensus forecast. Continuing claims for the prior week were revised modestly higher to 4.62 million. DJ30 -213.37 NASDAQ -25.55 NQ100 -0.9% R2K -1.8% SP400 -1.3% SP500 -21.56 NASDAQ Adv/Vol/Dec 676/2.90 bln/2015 NYSE Adv/Vol/Dec 649/1.50 bln/2401