My father has been with Amex since '93. If I was to have him apply for an Amex personal account and add me as a user, I could potentially back date that account to 1993? That sounds enticing. Now just have to tell my GF I don't need her Amex anymore
I would recommend he apply for a personal Amex CREDIT card, not a charge. For example, the Starwood, Hilton, or Delta card. That way the credit limit is clearly listed on your credit report as charge cards are treated differently.
He needs to make sure when he gets the new card, it says 93 on it (more than likely it will, but you never know). Amex will fix his card if they do not put 93 on it.
Once he has a 93 card, then he can login to their web site and add you as an authorized user, he will enter your SSN.
You will get the card in the mail and it more than likely will have 2013 on it (unless you had an Amex at some other point). Your dad/you will then need to call Amex and ask if they will change the member since date to match the primary account holder. Sometimes they do, sometimes they won't.
Give the credit report 1-2 months to update.
Your credit report shows an Amex credit card opened since 1993 with his credit line. If they only start him at $5k, after 60 days he can call in and have them up it to $15k (3x increase max at once) assuming his credit is good.
Your credit report shows an Amex credit card opened since 2013 with his credit line.