Yes I definitely see manipulation on L2 but that is when there is low volume and the # trades is low.  When a stock has 250+ in daily trades, manipulation is less of a factor, because the day traders take control and swing the puppy like a roller coaster.  That's how they make their money.  Personally, I think day trading is healthy for a stock.  When there are enough day traders regularly trading a stock, the longs benefit also. Day traders create action and excitement in the stock and  that draws in more traders and longs.  When we were doing 50 trades a day, ya there was manipulation.