Tyson Foods and NxStage Medical climb; Geo Group skids

Stocks that moved substantially or traded heavily Monday:

Tyson Foods Inc., up $3.60 to $66.90

The Spam maker raised the low end of its annual profit estimates.

Rockwell Collins Inc., up $8.07 to $127.07

Reuters reported that United Technologies made an offer to buy the aviation electronics maker.

Anadarko Petroleum Corp., down 52 cents to $44.37

Energy companies fell with the price of crude oil.

NxStage Medical Inc., up $6.53 to $29.67

Fresenius Medical Care agreed to buy the medical device company for $30 a share, or just under $2 billion.

Alibaba Group Holding Ltd., up $5.51 to $158.84

Alibaba and hotel company Marriott International started a joint venture aimed at Chinese tourists.

Geo Group Inc., down $2.04 to $26.02

The private prison operator posted weak revenue in the second quarter and its forecast disappointed Wall Street.

II-VI Inc., up $2.80 to $38.15

The laser and optics company had a much stronger fourth quarter than analysts expected.

KLA-Tencor Corp., up $3.18 to $92.01

Technology companies rose Monday as chipmakers did better than the rest of the market.

Armstrong Flooring Inc., down $3.03 to $14.25

The flooring company cut its forecasts after it said sales of sheet and wood flooring were weak in the second quarter.