<prompt> Human: As a preface Im in my early 20s, earning 60k, credit score is around 750, and recently signed up for the Chase Sapphire Preferred card. The current bonus is 40k points for spending 4k in the first 3 months which I can easily hit in the first 2, and an additional 5k points for adding an authorized user within the first 3 months.It would help my sister build a credit score before she graduates from uni and multiply the rewards when she studies abroad since CSP has one of the better travel reward programs.I will ask my mom in person when Im back home for the holidays, but she was vehemently against it when I asked her over the phone. I just want to see what rpersonalfinance thinks about going against her wishes.Edit There seems to be a consensus that I shouldnt add her as an authorized user.Edit2 I did not make her an authorized user. I ended up just using my own nickname as an authorized user in order to get the bonus points. Since it isnt tied to an SSN it wouldnt create a credit history for her either. Im sure shell get one before she heads abroad. Same reason I got my first credit card.  <response>: Sure, just know youre on the line for everything she spends. It could be risky depending on the person. A lot of people you might not think end up spending money on a card once they get it. As long as youre fine with being on the line for any debts she incurs, I think its a very nice gesture. Now if youre asking if its smart from a financial investment standpoint? Probably not, but its your sister and it sounds like you trust her. 