Noooooo. No, I don't..... Just a toady. I once had this gnarly little laptop, and wanted to make sure I kept it "clean" for trading emergencies. So I took the little IB corporate symbol -- the little red guy holding his hand up in a one-fingered salute in what purports to be a trading-floor manner?? You know it??? Yeah. I had that as my desktop. Sheeesh. Toady. (Or else, it's me giving the finger to the world. Hell! it looks just like that!)
Oops. Then it is probably an error. Definitely requires a call to customer service. I was too focused on the margin impact fields.
If I understand correctly, IB is worried about the worst-case scenario: 1) One leg is assigned early 2) The other leg is left open 3) You are not there to close it, you leave it alone 4) The market moves violently against your favour for the remaining leg 5) Since you are not there to exercise the last leg IB looks for cash rather than automatically trading away your positions. Perhaps this could be addressed with an option on the order: If one leg of a multi-leg option is exercised, immediately exercise the other legs. Is such a thing do-able with IB?
Great summary, HT, but it's not the whole story. OP Chubbly posted two pairs of screen shots showing CheckMargin shots, the second of which *violates* our little theory, to wit: if we can explain away the July (Sep17) v Dec (Dec17) difference (as European v American exposure), why for is that not duplicated on Chubbly's adroitly done June (Jun17) v EOM Jun (Sep17) (American v European exposure). I can *not* explain that one. Could be all kinds of reasons. Could be Chubbly holds some other spreads, with other available risk offsets! Could be that what IB thought was coded properly and permanently (only in CheckMargin), was muffed on the last CFTC rule change -- and if it weren't actually operational, no one would've complained because it lay hidden, until Chubbly clicked his mouse and posed the question. (Hell, it *could* be space aliens.) I dunno. But again, I would surely like to be in on that phone call. So, it seems, that after a nice tour through margin and CFTC and SEC minutia, we're right back at the original query. IB??? Any help??
Again I'd have to say it's not a CFTC rule both because as Chubbly showed other brokerages don't apply this rule and as I pointed out they're exposed to the same risk that a weekly expires inside the spread. Happy to be proven wrong if you can cite the alleged rule? It clearly is a software error, but good luck getting them to even understand it, let alone do anything about it.
Such an extraordinary initial margin is not a regulatory requirement and it is not SPAN. IB is discouraging you from trading of options with far (September 2017+) expiration. The liquidity is not great.
Why in the world would you discourage someone from providing liquidity where there isn't currently any, are you the liquidity police now? And why would liquidity have any impact whatsoever on a margin for a vertical debit spread, which as I've pointed out over and over is impossible to lose more money than you initially paid to establish the position? This kind of non-answer is exactly what I'm talking about when it comes to IB "customer service"!