NEW YORK - US stocks fell on Thursday, surrendering early gains as renewed concerns over bank loan quality dragged markets lower.

The Dow Jones Industrial Average fell by 301.07 points, or 0.65 percent, to 45,952.24. The S&P 500 sank 41.99 points, or 0.63 percent, to 6,629.07. The Nasdaq Composite Index shed 107.54 points, or 0.47 percent, to 22,562.54.

Ten of the 11 primary S&P 500 sectors ended in red, with financials and energy leading the laggards by losing 2.75 percent and 1.12 percent, respectively. Technology bucked the trend by adding 0.13 percent.

Regional lenders led the decline. Zions Bancorporation plunged 13.14 percent after the bank disclosed a sizable charge linked to bad loans from a few borrowers.

The sell-off deepened anxiety over the health of the banking sector, which has been under pressure following the recent bankruptcies of two auto industry-related firms. The failures have stoked fears of loose lending standards, particularly within the opaque private credit market.

"Following the prominent bankruptcies of Tricolor and First Brands, bank investors are rightfully on high alert for any change in asset quality trends," KBW analysts wrote in a note.

Market volatility surged as the Cboe Volatility Index spiked to its highest level since May. U.S. Treasury yields and the dollar both moved lower, with the 10-year yield slipping below 4 percent and the dollar index losing 0.4 percent.

On the economic front, the Philadelphia Fed manufacturing index tumbled 36 points to -12.8 in October, its lowest level since April and well below expectations for a 9.5 reading.