When you finance a car, whether you're buying or refinancing, the vehicle is collateral for the loan. Some lenders want a loan to be fully secured and won't provide a loan for more than 100% of the car's value. This is called the “loan-to-value” ratio or LTV. Other lenders make loans for more than 100% LTV, but usually only if the borrower has good credit. If you can refinance your upside-down car loan, it may be a way to get right-side up faster.