The S&P 500 kicked October off with a spooky start, as the index skidded 1.8% last week to close down at 1,025.21. However, the index closed out the third quarter with its best quarterly performance since 1998, gaining 15%. The S&P remains up 52% from its March 9 low and 10% year to date.

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

Winners on the week:

Company

Percentage Gain

Gannett (NYSE:GCI)

26%

Ameriprise Financial

18%

Walgreen (NYSE:WAG)

13%

Affiliated Computer Services (NYSE:ACS)

10%

Invesco (NYSE:IVZ)

9%

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

Losers on the week:

Company

Percentage Loss

Xerox (NYSE:XRX)

(19%)

MetroPCS Communications

(16%)

AK Steel Holding

(13%)

United States Steel (NYSE:X)

(13%)

Eastman Kodak (NYSE:EK)

(12%)

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

A look at some of the movers
Walgreen saw shares rise last week after reporting better-than-forecast September same-store sales. Sales jumped 5.3% on in-store flu shots and sales of general merchandise, which increased for the first time since May.

Shares of Xerox slipped last week after the printer and copier juggernaut acquired IT services company Affiliated Computer Services for $5.6 billion. As my Foolish colleague Anders Bylund writes, the deal follows a megatrend in IT, marrying Xerox's hardware operations with ACS' services operations to tap a $500 billion market.

However, investors grimaced at the deal's financing, which caused Xerox to load up on $2 billion in debt, pay out $1.8 billion in cash, and finance $3 billion via capital markets.

Eastman Kodak was among the week's biggest losers for the third straight week, after news that Kodak's chairman and CEO, Antonio Perez, will stay on through 2013. Investors fear the CEO's extended term signals no shift in strategy, notably in the company's unprofitable inkjet printer business.

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