With portfolio margin you can get up to 6.66 leverage in theory (for equities). An interesting question is, what is the maximum leverage that you can execute in the opening or closing auction?
For example, if you have a portfolio at 6.66 leverage and you liquidate the entire thing at the close (ie using MOC orders), you execute 6.66 leverage in the auction.
If you simultaneously open a new portfolio while closing the old one, you could execute a total of 2 x 6.66.. = 13.33x in the auction….