Actually, there are software platforms that daytraders use that allow you to put in an order to sell 10K shares, but only show it as a 100 share lot. When that gets filled another 100 shares is offered, until your 10K shares are sold. MM can see the 10K shares on Level 3 data, but us regular traders on see 100 shares and don't know about the other 9900 shares. So if it looks like 3000 shares would take you thru $2.50, that would be incorrect.