What's the difference between a co-signer and a co-borrower?

A co-borrower (or co-applicant) shares ownership of the vehicle and equal responsibility for the loan, and is usually on the title. A co-signer guarantees the debt but typically isn't an owner. Both are fully liable to the lender if payments are missed, and the loan generally shows on both credit reports. Spouses or partners who will share the car often apply as co-borrowers, while a parent helping a young buyer often co-signs.