They will til their stock is gone.
This is why the computers win, most always. If you have an automation desk, you will always have algos indicating if the activity is real or not. Based on density of trade vs. actual bid/ask. Ie, if my computer is reading and recording the data log of the system and it says there is 10k stock but it keeps passing more, then I need to slow down my buying. Known as latency effect. They will read the trade coming in and quickly fill more than what is indicated.
When you get into TSLA type trades, etc. - massive, uber speed, next to exchanges, serious type computer battles occurs. All computers, all day.
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