* JPMorgan falls, Wells Fargo gains after results
* Producer prices post largest increase in nine months
* UMich consumer sentiment index hits nine-month high
* Indexes down: Dow 0.7 pct, S&P 0.5 pct, Nasdaq 0.6 pct (Updates to afternoon session)
By Angela Moon
NEW YORK, April 11 (Reuters) - U.S. stocks fell in a volatile session on Friday as biotech shares resumed their downward trend and disappointing earnings from JPMorgan weighed on the financial sector.
JPMorgan Chase & Co shares fell 3.2 percent to $55.59 as the biggest drag on the S&P 500 after it reported a far weaker-than-expected quarterly profit as revenue from securities trading fell.
The S&P financial index lost 0.8 percent as the worst performing S&P sector.
Biotech and momentum stocks extended losses from the previous session's sharp selloff that sent the Nasdaq to its worst decline since Nov. 9, 2011 and the benchmark S&P index to its biggest fall since Feb 3.
The Nasdaq biotech index fell 0.2 percent after rising as much as 1 percent earlier. The Global X social media index, which includes Facebook and LinkedIn , fell 1.5 percent.
The Dow Jones industrial average fell 108.15 points or 0.67 percent, to 16,062.07, the S&P 500 lost 9.8 points or 0.53 percent, to 1,823.28 and the Nasdaq Composite dropped 24.298 points or 0.6 percent, to 4,029.808.
S&P 500 companies' first-quarter earnings are projected to have increased just 0.9 percent from a year ago, Thomson Reuters data showed. That's down sharply from the start of the year, when profit growth was estimated at 6.5 percent.
Shares of Wells Fargo & Co rose 1.3 percent to $48.33 after the biggest mortgage lender in the U.S. reported a 14 percent rise in first-quarter net profit.
Equities have been volatile this week, with Thursday's move a sharp reversal from gains Wednesday after minutes from the latest Federal Reserve policymakers' meeting suggested members were more likely to keep rates low than previously expected.
Since reaching a record intraday high on April 4, the S&P has fallen as much as 4.1 percent, while the Nasdaq has dropped 8.3 percent from its March 6 intraday high.
Even with the recent declines, investors appear committed to equities. Investors in U.S.-based funds poured $8.9 billion into stock funds in the week ended April 9, data from Thomson Reuters' Lipper service showed on Thursday.
The Thomson Reuters/University of Michigan's preliminary April reading on the overall index of consumer sentiment came in at 82.6, the highest since July, as both current conditions and expectations brightened.
The seasonally adjusted producer price index for final demand increased 0.5 percent last month, the largest increase in nine months, pointing to some pockets of inflation at the factory gate. (Reporting by Angela Moon; Editing by Nick Zieminski)