Affect of AU vs Primary on FICO scores

[Anonymous]

I'm sure this has been asked, but I'm having trouble finding a clear answer.

Does having an account marked as an "Authorized User" have an impact on the FICO score versus if you were the primary account holder?

Thanks!

[Anonymous]

Sure.  Becoming an AU on someone else's card can certainly affect your score in all kinds of ways:

    *  The balance can affect your utilization, as can the credit limit.

    *  The "date opened" field can affect your 'Age of Oldest Account" and (less importantly) your AAoA

    *  Any derogs (lates, etc.) associated with the card can lower your score

Etc.

[Anonymous]

Thanks. I mean more AU vs Primary for the same hypothetical account. If I were the primary account holder versus authorized, all other factors being the same, would the FICO score be different?

[Anonymous]

It's an interesting question.   It's hard to be able to answer for certain since FICO hides the details of its algorithms, and trying to create a test scenario would be so difficult (where you become the primary cardholder, do a bunch of testing, then somehow get it deleted outright from your reports, then become an AU on that very same card, then duplicate the tests).

What is known is that you can become an AU and it doesn't help you, because FICO somehow decides you aren't a "legitimate" AU (husband/wife, parent/child, etc.). 

You can also become an AU and the CC issuer can give you a different Date Opened than the original card holder.  That would be one more reason for a big difference.

Is there a practical reason you are interested?  Or is it just fun speculaton?  Either is fine, just trying to help.

[Anonymous]

Up until recently, my wife has had a significantly higher credit score. Because of that we've applied for three of our five cards in her name, getting us a much higher starting limit and interest rate. I've been an AU from the start on those, so I'm just curious how much of an impact that might be having.

[Anonymous]

Great.  That's going to take us from an abstract question that is hard to answer for sure, to a much more concrete question regarding your profile.

So for your reports (EQ, TU, EX)....

      How many credit cards appear in your name alone?

      How many other credit cards are listed on which you are an AU?

      For the AU cards, is the Date Opened listed the same as on your wife's report?