A collateral loan is also called a secured loan. It is a loan obtained from a banking or other financial institution, where in exchange, the creditor may sell that which is offered for collateral if the loan is unpaid. A collateral loan is often offered at a lower interest rate than an unsecured loan, because there is a guarantee of repayment should the borrower default on the loan.

A collateral loan may use different things to secure the loan. Often people use stocks or bonds to establish a collateral loan. They can use their ownership in property, where a portion of perhaps a home, or a piece of land, is set up as collateral. If the borrower defaults, he must sell the property to pay back the loan, and the lender has rights to sell the property also, even if only a portion of the full value belongs to them. In these cases, a lender would sell the home, and give the previous owner the monies not offered on collateral.

A collateral loan may also be based on expected collateral, like the expected return on a harvested crop, or on an investment. Occasionally, one can use property like high-valued jewelry as collateral, or other high-valued goods. This is rare, as most collateral loans are based on paper assets, or on real estate.

If the collateral given decreases in value and the borrower defaults, he or she will still be responsible to repay the amount at which the collateral was previously assessed. For example, a person borrows $100,000 on a home of the same value. If the home decreases in value, say to $75,000, the borrower must still pay back the full amount, as dictated by the terms of the collateral loan. If a borrower has defaulted on the collateral loan, his or her home will be sold. However, the borrower will still owe the lender $25,000. This may require the borrower to sell more possessions or enter bankruptcy.

In most cases, people will not borrow to the full value of a possession offered as collateral to avoid the circumstances described above. Instead, the collateral loan is usually only a portion of the full value of a possession, or of paper trading like stocks and bonds. People with a number of high value items, properties, or stocks and bonds can of course get larger collateral loans. However, with any loan, it is best to borrow only what one needs, since interest rates will still mean a higher payback than the actual money borrowed.