Market Insider

After-hours buzz: BIIB, DIS & more

Pedestrians walk near the New York Stock Exchange on December 19, 2016.
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Check out which companies are making headlines after the bell on Monday:

Biogen shares fell more than 2 percent in extended trade Monday after the company said it will appoint its chief commercial officer, Michel Vounatsos, as its new CEO. He is set to succeed current CEO George Scangos in January, the company told CNBC. Vounatsos has been with the company since April. He will be on CNBC's "Fast Money" on Monday to discuss the move.

Walt Disney shares inched higher after the bell on Monday, following reports that Walt Disney Studios was expected to hit a major milestone at the global box office, thanks to its $290 million global debut of "Rogue One." The studio anticipated hitting $7 billion at the global box office for 2016 on Monday, making it the first-ever studio to reach that threshold.

General Motors saw choppy trade after the company announced it will shut five U.S. auto assembly plants for varying durations in January. The purpose is to cut oversupply of sedans, which have fallen out of favor among U.S. consumers. In October, GM said it had increased its U.S. dealer inventory by 111,000 vehicles.

—Reuters contributed to this report.