Amex has had their head stuck in the ground on a huge huge problem if you like to keep business and personal separate. It has been brought to there attention at the highest levels and they still have not fully corrected the problem. But if you have a Membership Rewards account that is the same for biz and personal your business people can not only see your spend but before it was brought to the attention to amex your business people could see how much you spend on your personal card. Before the complaints someone on your business side could actually see what items you were buying on your personal card via the Membership Rewards portal. Not so great if you want to keep your business and personal information apart like any well run business would want to do.