GAC - The credit dept of brokerage firms are interesting. Although they have general rules they follow like $2.00 and higher is margin-able, some firms have stepped in margin rates. An example may be $2.00 = 30% margin and $5.00 = 50% margin. Each house or brokerage have there own general limits. Now the credit manager who's responsiblity it is to endeavour to limit the exposure of the house to undo risk can make a call on individual securities and clients at his/her's discretion. That may be for reasons that are totally irrelevant to your situation like overal exposure and limits of credit for the entire company(brokerage) that you would have no idea of and they have no obligation to inform you of. On the individual client side they may look at the concentration of your holdings and say to them selves; this client has 95% of his holdings in this one security we don't want any more exposure on that security for that client. 

There are many instances where credit managers butt heads with the sales dept. The credit manager usually wins. Risk reduction is a big issue for any brokerage, especially a bank owned firm.

These are just some examples of what could be behind RVX not being marginable with BMO in your situation but not exhaustive. Once upon a time I ran into a situation where a couple of series of BMO prefs where no longer margin-able at the brokerage I was dealing with. Those securities represented less than 3% of that account. Go figure that one out.

Looking forward to hearing what they have to say to you about this today.

tada