Different factors affect all orders, whether bid or ask, such as time and quantity. My sell orders are below 5000 shares, so neither my orders or others' will show up unless they are for 5000 or more shares on level 2 because the SP is below .50. Once SP reaches .50 or above, then 2500 lots will show up. At 1.00 or more then 500 lots show up. Whether you place an order at the bid or ask or in between, it is time stamped and put in queue. It's like being in line to buy a ticket. If you get out of the line, you have to re-enter at the back of the line if you still want a ticket. That's what makes it difficult to sell, there's many in line. It's much easier to buy.
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