Are there any qualification requirements in order to receive Portfolio Margining treatment on US securities positions and how does one request this form of margin?

Übersicht: 

In order to enabled for portfolio margining an account must be approved for option trading and must have at least USD 110,000 in net liquidating equity (USD 100,000 to maintain, once enabled). Account holders will also be required to acknowledge and sign the Portfolio Margin Risk Disclosure document and be bound by its terms.  

Portfolio margining may be requested through the on-line application phase (in the Account Configuration step)  or after the account has been approved. To apply once the account has already been approved, log into Client Portal and select the Settings and Account Settings menu options. In the Configuration section, click the gear icon next to the words "Account Type". There you may choose the portfolio margin treatment which will initiate the approval process.  Please note that requests are subject  to review  (generally a 1-2 day process) and may be declined for  various reasons  including a  projected increase  in margin  upon upgrade  from Reg T to Portfolio Margining.