They're calling it a "merger": http://www.elitetrader.com/vb/showthread.php?s=&threadid=77143 Unfortunately, the e-mail I received from ToS explaining the real deal has been deleted from that thread
My experience has been that even on American options they still look at the whole position. If you are assigned then margin comes into play. If you don't have enough in your account the account becomes "Subject to Liquidation". They will step in if they need to but not immediately. In fact they try to phone you up first rather than having some default 24 hour rule. I have been in an insufficient margin situation at TOS for several weeks and they did nothing. The amount was small. Before I dropped Fud-delity they liquidated a position less than 24 hours and for only $5.00 deficiency. This whole IB vs TOS is not an idealogy war. For me, and at the time, IB cramped my style with what I was doing with options.
IB are changing to position based marging from rule based in November according to the comments on suggestion 1046 on their voting system. didn't say which november though!
Yeah, that clunky platform is hard to beat I've tried. Even with a baseball bat. Before the Interactive Brokers evangelists takeover (they are even more extreme than ToS cult members) let's not forget a few cons: Unable to log in at weekends and forced auto log out every day. 100 market data lines limit. Great. Cancellation fees for option orders. Even better. Unable to properly margin broken wing butterflies etc. Really good for option traders! FWIW, I have accounts with both IB and ToS.
https://cpm.theocc.com/ This makes it sound like CPM is still a pilot program. It'd be great to have equity option margining closer to SPAN.
Yeah, that's solid. I am trying out a new one... termed "the stranger" I sit on my hand until it falls asleep and...