Does the factory warranty transfer when I buy a used car?

In most cases, yes. Factory bumper-to-bumper and powertrain warranties usually stay with the vehicle and transfer automatically to the next owner for whatever time and mileage remain. Some brands limit certain coverage, such as an extended powertrain warranty, to the original owner only, and a few require a transfer form or fee. Check the brand's warranty terms for that model year and ask a franchised dealer to confirm remaining coverage using the VIN.