Sunburn: SolarCity shares slumped 22 percent Friday, to $29.65 after the company said it plans to slow its installation growth rate to about 40 percent in 2016 from an 80-90 percent growth rate in last nine years.


Power play: Duke Energy, the biggest electric company in the U.S., said it will buy Piedmont Natural Gas for about $4.9 billion. The deal will give Duke about a million new customers in the Carolinas and Tennessee. Piedmont shares surged 37 percent on the news Monday, to $57.76, and closed Friday at $57.31.


Shortfall: Cummins dropped 7.4 percent, to $103.85 Tuesday after the maker of generators and engines posted disappointing third-quarter results and cut its outlook for the year. The company said it will eliminate up to 2,000 jobs because of a slowdown in the global markets. Its shares closed Friday at $103.51.


Gainers: Northrop Grumman surged 7.2 percent, to $193.58 Wednesday after the defense contractor said it received a contract worth up to $80 billion to build new bombers for the Air Force. Northrop Grumman stock has been trading at all-time highs. The stock closed the week at $187.75.


Stalling: Ford reported improved sales of its new F-150 pickup truck, but its net income fell short of Wall Street estimates and the shares lost 5.1 percent, to $14.89 Tuesday. Shares finished the week at $14.81.


Big Pharma talks: Allergan, which makes Botox, jumped 8 percent to $310.14 Thursday after saying it has held talks with Pfizer about a sale. Both companies have long history of deal-making. About 18 months ago Pfizer tried to buy AstraZeneca. Allergan shares finished the week at $308.47.


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