I believe that's an order from earlier in the day that was posted out of order. It may have been placed with the MM early in the day and it took them all day to fill it. It's quite possible that the MM had to use shares from his/her own supply to get it done. (Or borrowed them from another MM or created them out of thin air, who knows). If the MM actually used his own shares, you can bet he/she'll be looking for cheapies to replenish come Monday.
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