The S&P 500 kicked off the unofficial beginning of fall with a strong start, finishing last week at 1,042.73, up 2.6%. Last week defied now longtime calls for a correction in what is historically the most lackluster month for stock market performance. Friday marked the eighth anniversary of 9/11, and coincidentally, the S&P sits very close to the 1092.54 it sat at eight years ago.

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

Advanced Micro Devices (NYSE:AMD)

25%

Genworth Financial (NYSE:GNW)

22%

Titanium Metals

18%

MetroPCS Communications

18%

Chesapeake Energy (NYSE:CHK)

18%

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

Losers on the week:

Company

Percentage Loss on the Week

Kraft Foods (NYSE:KFT)

(7%)

Fifth Third Bancorp (NASDAQ:FITB)

(7%)

American International Group (NYSE:AIG)

(6%)

Ameren

(5%)

Family Dollar Stores (NYSE:FDO)

(5%)

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

A look at some of the movers on the week
Last week, Kraft Foods made a $16.84 billion bid to acquire British confectioner company Cadbury. However, Cadbury rebuffed Kraft, citing the offer as too low. There is speculation that Kraft will boost its offer for the candy maker, as the company views the acquisition as a good next step in its margin-boosting efforts. As my Foolish colleague Mike Pienciak writes, if a deal were to materialize, the synergies would be beneficial over the long term.

AMD is launching a new graphic chip line that the computer chip maker says will trump competitor Nvidia. AMD says the graphic chips enable three-dimensional capabilities for video games as well as other technologies and will be two and a half times faster than AMD's current chips. The company also introduced a new high-powered chip that can power six computer displays at one time, as opposed to only a couple of displays.

Shares of Fifth Third Bancorp took a beating last week after banking analyst Dick Bove of Rochdale Securities said he does not expect the regional bank to turn a profit until 2011. The analyst did note the bank's going concern is no longer a question mark, though.

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Jennifer Schonberger does not own shares of any of the companies mentioned in this article. Chesapeake Energy is an Inside Value recommendation. Titanium Metals is a Stock Advisor pick. The Motley Fool owns shares of Chesapeake Energy and has a disclosure policy.