I'm may be partial but if the card will report you as AU I would not recommend being a co-borrower. You rare giving them the right to pull your credit because as a co-borrower you will be equally responsible for the loan. This is probably good for the bank regardless of what your current score is because if he happens to default, they will come after you just as hard to collect their money, it gives them more than one out. Is your brother going to give you free reign to the credit avail on this card? This account will not only reflect on your report but will show you equally responsible for it. If a lender is deciding whether or not to increase you or extend credit, would this be a limit that would be beyond your sole ability to pay should it become maxxed out? If so, you could find yourself denied for additional credit simply by having access to a large unsecured line of credit.
An AU status will increase your FICO score without the added responsibility of repaying credit you don't have access to. IF something were to happen to your brother (god forbid) are you both willing and able to repay the current balance on this card? You would be held liable for it. Think long and hard before becoming a co-applicant on anything.
FWIW I put my 13 yr old on two cards AU only and before opting him out, he was getting offers from the likes of AMEX and discover AU status only.
HTH
Message Edited by Brammy on 04-02-2007 10:28 PM