Someone got scared and sold the rest of their investment. Remember, every single day there are going to be people who get scared. Just wait, there will be BIG investors, besides who doesn't want part of a company that makes money....
It's usually called painting the tape. They're probably trying to keep this low since there is buying pressure and they're short.
However, this might have been a t trade. Normally, trades show up on the time & sales chart as they are processed. However, if a MM missed entering something during the day, they pick it up and report it as a t trade at close. Thus, it hits the price action and reflects a different price from the bid/ask.
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