Stocks Post Worst Weekly Loss in 4 Months

Stocks finished flat Friday, but dropped more than 2 percent across the board for the week, as ongoing worries over global growth trumped a better-than-expected earnings announcement from JPMorgan Chase.

All three major indexes logged their biggest weekly drop since the first week of June.

"If we break 1, 420 [on the S&P], it's going to raise some questions…simply on the cocktail napkins, we're beginning to see some pressure building, " said Art Cashin, director of floor operations at UBS Financial Services.

The Dow Jones Industrial Average eked out a tiny gain of 2.46 points, or 0.02 percent, to close at 13, 328.85. BofA led the blue-chip laggards, while Boeing gained.

The S&P 500 erased 4.25 points, or 0.30 percent, to end at 1, 428.59. The Nasdaq slipped 5.30 points, or 0.17 percent, to finish at 3, 044.11.

The CBOE Volatility Index, widely considered the best gauge of fear in the market, finished near 16.

For the week, the Dow slumped 2.7 percent, the S&P dropped 2.21 percent, and the Nasdaq tumbled 2.94 percent. AT&T led the weekly blue-chip laggards, while McDonald's finished higher.

All key S&P sectors finished in the red for the week, led by telecoms .

"When the S&P does find a short-term bottom, I don't expect a bounce to lift all boats, " wrote Elliot Spar, market strategist at Stifel Nicolaus. "There has just been too much technical damage done to individual names that they will struggle to make headway. Thus, you'll have to be very selective in playing an upside move."

Stocks saw a brief lift after a report showed consumer sentiment rose in October to its highest level in five years , according to the Thomson Reuters/University of Michigan's preliminary reading.

Among earnings, JPMorgan posted quarterly results that topped expectations as the financial giant began to put its "London Whale" trading losses behind. Still, shares ended in negative territory.

Rival Wells Fargo fell after the company reported earnings that were a penny better than estimates, but revenue was lighter than forecast .

"Their profit margins are being squeezed," Cashin said of the sector. "And you've had two separate members of the Federal Reserve talk about capping the size of large banks…so profit margins are coming into pressure and long term growth is starting to look doubtful."

Other major financials including Citigroup, Goldman Sachs, Bank of America and Morgan Stanley are scheduled to report earnings throughout next week.

Apple is expected to unveil its iPad mini at an invitation-only event on October 23, according to tech blog AllThingsD, citing sources.

Wal-Mart gained after Jefferies boosted its rating on the big-box retailer to "buy" from "hold."

AMD plunged after the chipmaker cut its third-quarter revenue guidance , citing weak product demand, prompting at least 12 brokerages to slash their price targets. Rival Intel also slipped to trade near a 52-week low.

Weak global demand has raised investor worry over the third-quarter earnings season. According to Thomson Reuters, earnings are expected to decline 3 percent from a year ago, the weakest since 2009.

Workday skyrocketed more than 70 percent in its market debut on the NYSE. The cloud-computing company opened at $48.05 a share after pricing shares above the expected range at $28. Workday's IPO marks the second largest in the tech sector this year after Facebook .

Also on the economic front, producer prices rose in September as the cost of energy surged, according to the Labor Department.

European shares ended lower as Spanish Prime Minister Mariano Rajoy continued to deny Spain needs a full bailout. Investor sentiment remains subdued on Europe after this week's gloomy economic forecasts for the continent from the International Monetary Fund. (Read More: EU Wins Nobel Peace Prize)

Meanwhile, euro zone industrial production gained in August, beating expectations for a decline.

—By CNBC's JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)

On Tap Next Week:

MONDAY: Retail sales, Empire state mfg survey, business inventories, credit card default rates reported; Earnings from Citigroup
TUESDAY: CPI, Treasury int'l capital, industrial production, housing market index, News Corp shareholders mtg, Target media day, 2nd Presidential Debate; Earnings from Coca-Cola, Goldman Sachs, J&J, United Health, Mattel, PNC Financial, State Street, IBM, Intel, CSX
WEDNESDAY: Weekly mortgage apps, housing starts, oil inventories; Earnings from BofA, PepsiCo, Bank of NY Mellon, Blackrock, Northern Trust, US Bancorp, AmEx, Ebay
THURSDAY: Jobless claims, Philadelphia Fed survey, leading indicators; Earnings from Morgan Stanley, Phillip Morris, Travelers, Union Pacific, Verizon, Fifth Third, Huntington Bancshares, KeyCorp, Nokia, Google, Microsoft, AMD, Capital One, Chipotle, E-Trade
FRIDAY: Existing home sales; Earnings from GE, McDonald's, Schlumberger, Honeywell, Edward Lifesciences

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