My experience has been that AMEX provides higher limits than VISA and will work with you to increase them. They will also "reallocate" credit amount different AMEX cards. I had a limit of $40000 on a SM amex, got a SPG amex with a limit of 20,000. reallocated 38000 from the old SM card to the new SPG giving me a limit of $58000 on my SPG line. This is on a business account where I use it for several major vendors each month. This reallocation is really handy if you are going to churn cards and need a high limit for business purposes.