It's called a Short and Distort tactic of shorting a stock. It's very illegal. The unethical groups out there sell shares of the stock they don't own (this is called shorting) and then use any tactic they can to drive the price of the stock down and low as they can get it such as hiring people to bash stocks by any means necessary to start the panic selling which in turn triggers stop loss sell orders until they get it to the price they want then they buy up all the shares they need to cover their short and then some and start pumping the price back up and sell them off for big profits.
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