IMHO, (this is a question I doubt anyone except those in power at Amex can answer with authority), no way.

IME, there is no connection between deposits and credit limits at the big card issuing card companies. All is separate, except, perhaps, if you really have a lot (way over a 100K, closer to a $million) and have a private banker connection.

You are, most likely, the "victim" of Amex's response to the credit crunch and its stupendous fears of not getting paid back--which you are not likely to be able to do anything about.

Perhaps it would be best to look for another issuer which has loosened up a bit lately. UAL cards from Chase or AA from Citi come to mind. Not quite as good as the Starwood Amex--if that is one of the cards you are talking about--but, what can you do with Amex--at least, right now ...

By the way, IMHO, 1.3% is not such a good rate.