Quote from Options12:
It should be pointed out here that in a Portfolio Margin account, all long options positions, even if fully paid for, appear to be automatically pledged to the OCC and/or the broker-dealer. The broker-dealer also appears to have an automatic lien on long securities even if they are paid for within a Portfolio Margin account.
If this does not apply under IB's rules for Portfolio Margin accounts, please let me know.
This lien provision is applicable to all portfolio margining accounts regardless of which broker they are carried at and is noted in the disclosure agreement that all portfolio margin applicants must acknowledge. The reasoning behind it is a follows:
Customer positions are carried in an omnibus account held by the clearing member at OCC
(i.e., OCC does not know the identity of the beneficial owners of the contracts). Since long options are securities which are paid in full and subject to segregation just like a fully-paid stock position, they are segregated by OCC from customer short options. The effect of this handling is that the broker is not provided any margin relief from one customer's long option contract against another cutomer's short contract. It also means that if the clearing firm were to fail, all the long contracts (i.e., assets) would be available to SIPC as part of pool of collateral available to meet customer claims (whether SIPC decide to liquidate them to cash, transfer or return to clients is at their discretion although as a long option is viewed as a wasting asset and since SIPC likely has no market direction bias, it's reasonable to assume that they will liquidate them to preserve known asset value).
While longs are, by default segregated, a broker is allowed to unsegregate contracts if the Reg T client has a bona fide spread position. Logically, this is intended to provide the broker with margin relief at the OCC level similar to that which he has provided to the client. This is a very straightforward decision in a Reg T account as spread margin relief is offered and can readily be identified on a contract vs. contract basis. This is not the case with portfolio margin accounts in which margin is computed using a modified VAR model and through which margin offset between longs and shorts is provided on a dollar measure via the pricing model as opposed to contract measure. Given the operational impracticality of requiring brokers to execute the large scale calculations necessary to determine which long options and in which quantity to have OCC unsegregate and the fact that portfolio margin clients are generally afforded greater leverage and assumed to be sophisticated individuals subject to higher minimum requirements, the regulatory decision was to simply unsegregate all portfolio margin account long contracts at the clearing level and have this disclosed through the agreement.