How about calling directly the lessors ? The list (contact persons and phone numbers) can be found from this page: https://www.cmegroup.com/company/membership/membership-and-lease-pricing.html
They said this "Please note that if you are looking to lease a seat, IBKR has an internal equity requirement that must be met before we would guarantee a customer's lease. This does not apply to purchased seats." The internal equity requirement they quoted me is ridiculously high.
It's just a rule of IBKR (not exchange) ?! Ask others. It's a same situation as with their sky high intraday margin requirements compared to for example AMP Futures (ES $15k vs $0.4k -> 37x).
I have spoken with some other brokerages that do it but a lot of them have worse margin requirements - I don't trade E-Mini futures back and forth all day so the 300-400 intraday margin doesn't help me. Also most other brokerages even the institutional prime brokers I have spoken with don't offer ETFs and futures in the same platform, don't offer FX spot trading or other things that would hurt my top line. That's why I am now trying to get this done on IBKR.
That intraday thingy was just an example of the differencies between the brokers... How about this ? Matt Zimberg, CEO, Optimus Futures, LLC www.optimusfutures.com TF: 800 771 6748 Local: 561 367 8686 Questions?: general@optimusfutures.com That guy is very helpful and may know a solution for you.