Anyone can do it by bid whacking with small orders. Some even post disparaging remarks to go along with the bid whacks. Once the price gets walked down they buy back in with larger orders. At least that is the MO but it doesn't always work that way or they make less then a long does by staying in.
The best example is the video Crammer did about how he would go about shorting a stock when he ran his hedge fund. The video was so incriminating it was pulled.
There are many ways. Lets keep this discussion short however. I would like to keep the topic on HNSS.
Flippers will often bid wack thin BID support in order to lower the BID and increase the spread. This increase in the spread reduces the incentive for a buyer to hit the ASK. The flipper will then put a BID in to purchase shares from those who are unwilling to wait to sell shares at the ASK.
Lower BID. Less buying pressure to sell at the ASK. Increased incentive to sell at the BID.
There are many ways, although that is probably the most used one.
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