I noticed when I was buying a smaller, non-marginable stock that IB's PM requirements can exceed 100%. If you try to buy $10k worth of non-marginable stock, it will take $11k worth of initial margin since this recent change a few weeks ago took effect. If you have a PM account and also hold any non-marginable securities, it may be worth having a separate Reg T margin account where those can be held at only 100% instead of 110%. I am told there are no plans to apply this 1.1x initial margin rule to non-PM accounts.
IB. Sorry I wasn't clear (edited post above). Their recent conservative policy towards PM accounts means everything has an initial margin of 110% of the maintenance margin, which can lead to silly results sometimes. In an extreme case of only buying nonmarginable small cap stocks, you would only be able to buy $91k for every $100k in cash, and the rest would sit idle. Less than 1x leverage for having a PM account, when a regular cash account with let you at least invest everything!
Stay away from margin account , use margin if only you invest in dividend paying stocks. Margin trading is the biggest contributor to losing accounts.
Of course arguably if you've got a losing account, you should stay away from all brokerage accounts! Also, see my username .
I see that this is fixed in my account as of today, possibly it was sooner - long positions have a max of 100%. It is still the case that non-marginable short positions in an IB PM account require 110% of their normal margin amount. Until this policy changes, it may make sense to short non-marginable securities in a separate reg T account.