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I have both a personal AmEx and a Business AmEx. Both cards I have used and have paid on-time 100% of the time at the very least the amount due, but usually an amount over what is due in order to maintain a manageable balance. I had a very good credit score and recently when I cosigned for a friend on an automobile, she fell into a hard time and had several incidents of being late on the car payments. This unfortunately caused my credit score to drop. In order to mitigate the late payments, I paid off my friend's car for her and made a deal with her on payments that would work for her. American Express out of the blue, because of this lowering of my credit score (nevermind my stellar payment history to them and all other creditors) choose to lower my credit limit to the balance I owed on the cards, thus making them useless and unuseable. This was at a time when I had several important business trips to make that would have solidified future business for my company. I received no warning, no call, no questions in regards to this action... just an "FYI" letter after the fact. I have since paid off my personal card and will soon pay off my business card and do not plan on using American Express again unless this practice changes and I feel confident that I will be financially safe using them again.