Though the S&P 500 started out the year strong, the index skidded 1.6% to 1,073.87 in the last week of January. For the month, the S&P 500 fell 3.7%, marking the worst monthly performance since February 2009. Sovereign debt concerns along with skepticism about the economic recovery rattled markets last week, despite strong earnings and a stronger-than-expected fourth-quarter GDP number.

Pops and drops
Here are the five biggest S&P 500 upticks and five biggest S&P 500 drops of last week (measured Friday close to Friday close):

Winners on the week:

Company

Percentage Gain on the Week

Eastman Kodak (NYSE:EK)

38.8%

Genworth Financial (NYSE:GNW)

11.5%

Sherwin-Williams (NASDAQ:SHW)

9.2%

Tellabs

7.9%

Zions Bancorp (NASDAQ:ZION)

7.4%

Source: Capital IQ (a division of Standard & Poor's).

Losers on the week:

Company

Percentage Loss on the Week

United States Steel (NYSE:X)

(19.2%)

Qualcomm (NYSE:QCOM)

(16.2%)

Avery Dennison

(15.8%)

Motorola (NYSE:MOT)

(14.7%)

LSI

(12.9%)

Source: Capital IQ (a division of Standard & Poor's).

A closer look
Despite the selling pressure, there were some bright spots. One big surprise was Kodak. The photographic equipment company posted its first quarterly profit in five quarters thanks to inkjet printer sales, cost-cutting efforts, and royalties from the company's digital imaging technology. Earnings crushed analysts’ forecasts, sales rose 6%, and gross margin increased by 14 percentage points to 34.4%. Kodak's CEO, Antonio Perez, said the company gained market share in its core digital business and that the company's "momentum is returning." The quarterly report was welcome news, as Kodak's business has been struggling for some time, in part because of its late adoption of digital photography technology.

Similarly, shares of Genworth Financial popped last week after the insurance company swung to a better-than-forecasted fourth-quarter profit. Results were owed to a narrowed operating loss in its U.S. mortgage insurance unit. Investors cheered the results as an easing of the pressure of the financial crisis on Genworth's business.

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Fool contributor Jennifer Schonberger does not own shares of any of the companies mentioned in this article. You can follow her on Twitter. Sherwin-Williams is a Motley Fool Stock Advisor recommendation. The Motley Fool has a disclosure policy.