<prompt> Human: I have a question for you all. My older brother 24 is wanting to get a new car on a loan. He applied for loan at the dealership and got denied for lack of credit history. He has had one card for little less than a year.Me 22 have been interested in credit and the idea of churning for quite some time now. Want to get really involved once my income goes up after graduating. I was wondering if it would harm me, or even benefit me to co-sign for him.Information:Brother: 24yo, TN, 80kyr. 1 credit card at local bank little less than a year.Me: 22yo, IL, Go to graduate school and profit about 400month through stem program. 758 credit score. Discover it 3 years. Retail credit card 2y6m. I am very close to my brother and he hasnt even asked me to cosign, just that he got denied for lack of credit history. He said that they told him if someone our parents would cosign that they would accept. I know he will pay everything on time so I am not worried about that. I just want to know if cosigning will harm me. I know they will have to do a hard credit check which isnt beneficial but not too harming. I also plan on applying for a CF card tomorrow to get the sign up bonus LET THE CHURN BEGIN. Also could it help me? After the initial credit check that lowers my score, wont my score go up for having addition credit through the loan? Assuming he makes all payments on full and on time.  <response>: Buying a 70k car on a 80k year salary... He shouldnt be buying it at all. Talk about being car poor. 