The AU on my Ameriprise World Elite personal mastercard had a different number than my card.

My employee has a different card # as an AU on my Chase Ink acct.!!

All three of my Aadvantage Executive Mastercards have the same number. My daughter spent a year at King's College in London (the card never seemed to cool off) and her UK charges never impacted our ability to charge on the same card number in the U.S.

No problem reaching $40,000 12-month spend for 10,000 EQM that year...

See previous posts and responses below:

reclusive46 - sorry I didn't notice your question. Personally, this hasn't occurred to me, but it did to my parents many times where they sometimes go abroad separately. I don't recall them mentioning that it should ever be an issue. Right now, they switched to using Amex Plat so each card has a different number, but in the past they had a Visa with no forex fee.

so interesting to see this post from 12 yrs ago. wow.

good to see someone like MIA knows what theyre talking about.

altho adding AUs is discussed often, i never see the finer details like card number / online access / management etc.

for anyone like me discovering this post, FYI:

amex + barclays + cap1 (personal) - all different accnt numbers. this is ideal.

but all other personal bank cards give same copy info as the primary user. i hate this so much. bofa citi WF USB discover etc all do this.

at least all business cards have different numbers. i have not seen any bank issue employee cards w/ same info as primary. that would be stupid.

also, amex def has the best online support for AU management w/ settings. cap1 is not bad either. not sure which one is the most terrible tho. chase and USB kinda suck.

Here are some other ones I've had before that definitely have unique numbers for AU:

Comenity Caesars Rewards
Citi Retail Shop Your Way
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I can't believe that 12 years down the line Chase still hasn't switched personal AU cards to have unique numbers like Amex does. It absolutely drives me nuts.

Once upon a time my wife's cards were issued not only with the same number, but with my name embossed on the front, and her signature on the back.

Many HSA (health savings account) debit cards are like this. There is no such thing as a joint (or even family) HSA account (though a family contribution limit exists), so whoever opened the account gets their name on the account and dependents (spouses, kids, etc) who might need to use the funds get an identical card to the primary, only they are supposed to sign the back. And share the same PIN, IIRC. Crazy.

I've always wondered if two people using the same card number as an AU, would hit a fare cap on transit twice as fast, like in NYC or London. Since they both have the same CVV and Exp Date, why wouldn't the system recognize it as the same card. As long as they don't travel together, the system thinks its two different trips each time?

Not that I encourage this type of behavior, just out of curiosity...

Even though the account number, expiration date, and CVV are the same, the contactless chips are not identical.

This is true, but I'd be willing to bet it could still cause issues for some transit systems where they aggregate your charges for the day. Just because they have access to more detailed information through the chip doesn't mean some developer didn't use the card number as the primary key in the database.

Previously it was mentioned about hitting fare caps, but the place where I think it would be particularly bad is those transit systems that track your in & out places. Once card X has entered at a location, they can't enter again without exiting (so it knows what fare to charge). So if person A with card number X enters and their significant other with AU card X tries to enter behind them, it might not work.

Again, this assumes that someone used the card number as the key in the database, but I'm also certain there is a system out there where this at least WAS a problem at some point.

My wife is an AU on my Citi Costco card and her account number is different than mine.

I think Costco mandates this due to membership / picture on card requirements.

Apparently Chase is now doing this, at least for Sapphire Reserve accounts: https://www.flyertalk.com/forum/chas...t-numbers.html