The S&P 500's Biggest Movers

The S&P 500 soared 3.5% last week to 1,102.66, in the wake of European stress tests, a renewed focus on good corporate earnings across sectors, and General Electric's announcement that it would raise its quarterly dividend by 20% after cutting it last year.

Pops and drops 

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

Winners for the week:

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

Losers for the week:

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

A closer look
Shares of Genzyme surged last week, amid takeover talk surrounding the struggling biotechnology company. French drugmaker Sanofi-Aventis has made an informal overture to purchase Genzyme, which makes drugs for rare genetic diseases. In the wake of the manufacturing problems it has suffered, Genzyme is reportedly considering Sanofi's offer, but a price has not yet been named. Other logical contenders could include Johnson & Johnson and GlaxoSmithKline. Glaxo is rumored to have put out feelers, but nothing has come of that.

On the flip side, pharmacy benefits manager Medco Health reported better-than-projected second-quarter earnings. However, investors sold the stock after the company forecast weaker proceeds from new introductions of generic drugs in 2011-- a major source of profit for pharmacy benefit managers. In addition, though Medco predicted better-than-expected earnings for this year, the company said earnings per prescription would rise less than previously forecast. Both of those outlooks bode ill for Medco's margins. Competitors such as Express Scripts sold off in the wake of Medco's report.

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