It seems to me that Amex is walking a thin line here.

Of course they want to reduce their exposure to defaults; that is understandable.

But if they cut a business' credit line too much, that could actually precipitate a business failure. And how will Amex get paid then if the business fails? They'll have to wait in line to get paid, which may or may not ever happen.

There's a "vicious circle" dynamic here that is very scary.

Also, of course it's a wise idea to have more than one line of credit and not be dependent on just one, but in the current economic climate, as has already been mentioned on this thread, one's "fallback" line might be reduced or closed with little or no notice.

Anyhow, best of luck to the OP and other businesspeople who are affected by this. Scary times indeed.