Quote from Options12:
The 605 reports would probably be the better report for comparing quality of fills.
The 606 report shows venues.
IB's 2011 Q4 606 reports shows BOX as the venue which received the greatest share of non-directed market orders for options:
6. Boston Options Exchange (âBOXâ):
Percentage of total non-directed ordersâ¦â¦.. 4.3%
Percentage of non-directed market ordersâ¦.. 25.0%
Percentage of non-directed limit ordersâ¦â¦.. 3.4%
Percentage of non-directed other ordersâ¦â¦.. 9.1%
http://www.interactivebrokers.com/en/general/about/brokerDealerReports.php
What is the BOX's overall marketshare? Like 3%? Oh but IB owns a lot of the BOX.