Sounds like a great way for junior traders to practice shafting small traders, from their home computers.
Not really kidding, I knew a guy who said HE had been a bored junior trader for a market maker, and on thinly traded stocks they would play with the bid and ask to try to get a small trader to pay too much (or to sell for way too little). He said they viewed it as a game.
I have not idea whether that kind of stuff still goes one, this was about 5 years ago that he recounted that story.
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