======================Quote from flyers&divers:
an addition to the above post:
A lot of the MM's are not independent solo operators but trade for a firm, they may make markets on several names and their trades are fed in their mother computer. There are people upstairs monitoring the combined position to make sure that the firm's exposure is not too lopsided.
If the MM by any chance could or did not hedge their side of the trade after filling your order the upstairs people may hedge it in the process of costantly working on the global hedge.
Also think of the MM as a person keeping 7 plates swirling up in the air. While the are definitely working to have an edge and make money they are too busy for intricate games on each order.
When you are submitting an order on a slow option chain it does not mean that they are asleep at the other end because they probably handle many other names.
As far as buying on the bid and selling on the offer, even if you were personally standing there you could not do it unless you vere experienced and agressive so don't even dream about it from upstairs.
In addition to the above post;
selling calls on the offer,[closing long position on offer] dont know much about that,
perhaps i dont give enough time like limit order buys.
As far as buying on bid on high liquid options, better chance of that occasionaly;
and different & even more so if underlying ''wiggles'' or pullbacks,and the buyer isnt in a hurry to cancel.
