Okay, I didn't bother to read all the documentation, thus I wasn't aware that adding my 20-year son as an authorized user would impact his credit, I didn't even think he had any credit to begin with. However, Discover already gave him a credit card and his mother co-signed on his current car loan. So he was already establishing credit
My son has Credit Karma on his phone, and today he told me someone had started a new Chase credit card account under his name. I explained I had recently added him as an authorized user on a United card to get 5k miles. But, I also wanted to give him a Visa card for his impending trip abroad with his girlfriend. They have not yet decided if they are going to the Netherlands, Brazil or Japan. But, I assured him that his Discover card would not get him far in any of those countries, and a Visa card would be his best bet for a credit card (he has a Chase debit card for his checking account). He wasn't too impressed as he pointed to the app on his iPhone. His credit score had dropped 68 points once the AU card was opened in his name. He also assumed it was fraudulent and had already notifed Credit Karma that he had not opened that account. A major point of concern was that it showed an $1100 balance - a result of my recent purchases - which surprised me. I understood that I was on the hook for paying the card, not him. So, I don't understand why the balance of activity on MY CARD showed up on his profile.
Anyways, I assured him the balance seen on his credit report was only temporary and by giving him a card as an AU, it would eventually help increase his credit rating over time. He didn't seem too impressed, and it was awkward. But, I do think I did the right think by getting him his own Visa card as a backup when he is in a unfamiliar, foreign nation. Oh, and I forgot to give him the actual card today. It only has a $1000 limit, thankfully.
So, I hope my experience might help others avoid a surprise, when adding a family member as an AU.

Yes, when I added my one of my children to be authorized user (AU), as young as 14 for AmEx, I always discussed it in advance.

When their credit scores rose above mine, I removed them as an AU.

lol when mine were younger I too added them so they could have use in case of emergencies (they knew) Had NO idea until oldest was young college age & first year away went to a local bank to open an account & was told his credit score was above 800! I later found out both had scores this high because of being on my account for the years they had been (I did not remove them either) Fast forward to today… they are independent adults, both quite financially savvy & conscious about their credit scores/situations etc, so for us, although initially an unintended outcome, it proved to be a “gift” per se, ie. not having to start out at the bottom, establishing credit, etc, so in the end, a very good thing as it taught them a lot too!

Most credit cards, Chase included, don't issue new numbers for AUs. They can't really tell who's charge is who.

I'm also a bit surprised you're surprised by this. They literally say they will share the info with the credit bureaus when you add an AU. It's also literally one of the major reason people add kids as AUs. It's the easiest way to create a deep credit report before they even turn 18.

Agreed, BUT:

1) Discover owns the Diners Club network, and Discover cards should be accepted by Diners merchants. As a practical matter these are likely to be airlines, intercity rail, chain hotels and high end restaurants.

2) When traveling outside the USA I think it is best to have both MasterCard and VISA from different issuers, because some merchants accept only one of those, and there is always the possibility that a card issuer will shut down a card if international use is not part of the cardholder's history.

My daughter was added as an AU on my JPM Reserve card before she was two months old.

Why? I've added our toddlers to a couple cards to build their credit age, but I wouldn't pay for it. It'll be at least 10-15 years before there is any need for them to have their own actual card to spend on. Is there something I'm missing that would make it worth paying $75 a year for?

So, want to add my kids as AUs to one of my cards to build their credit. Obviously not to premium cards that charge for AUs, as they won’t actually use them. Never done this before, so a couple of things I’m wondering about:

- is it better to add them to a card I use for everyday spending, so racks up more charges (I pay off every month), or better to use a card I use on occasion?
- Would it help to add them to more than one, and if so, is it beneficial for a second card to be from
a different issuer?
- I assume at least with Chase, where AUs share card number with the primary, that it doesn’t make a difference whether I sock drawer their physical cards and just use mine as I do today, or if it is beneficial to put a charge or two on their specific cards. Does it make a difference with an issuer like Cap1, where AUs get a different card number.

appreciate any insight.