There is already clean-coal technology in existence. Billions of dollars have been spent over the years retrofitting older coal-fired power plants, and regulations are in place that mandate use of "cleaning" technology for any new plants.
A Trump victory, which doesn't appear likely, would have zero effect on the stock price. Besides, he would be much more likely to remove coal industry regulations (like ones mandating cleaning) than he would be to increase regulatory oversight of the industry (which would be required to nudge the technology forward).
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