Many vehicles are bought using some sort of finance agreement. Some of these agreements will give the finance company an 'interest' (ownership) in the vehicle.
If a finance agreement is still active when you buy a vehicle, the vehicle will not technically belong to you. The finance company could decide to repossess it at any time.
To avoid this, the previous owner will need to pay off any amount still owed before you buy the vehicle.
Learn more about different types of finance you may see on a vehicle check report.