What is the difference between a co-signer and a co-buyer?

A co-buyer, or co-borrower, shares ownership of the vehicle and responsibility for the loan, and is usually listed on the title. A co-signer guarantees the loan and is fully responsible for payments if the main borrower does not pay, but typically is not on the title. Both see the loan on their credit reports. Before agreeing to either role, understand the risk; the CFPB at consumerfinance.gov explains co-signing in plain language.