Co-signing on a loan reports on the credit reports of both the primary signer and the co-signer equally. I co-signed a loan for my son and this loan has shown up on my credit report since it was opened. The good news is that if you pay the loan on time, the information will report favorably for both you and the co-signer. If you do not pay on time [like my son who was payment late every month] the information will report negatively for both you and the co-signer. I finally had to take charge of the loan and make my son pay me so that I could be responsible for paying the lender on time.