Mortgage that sits behind the first mortgage in repayment priority and lets owners borrow against home equity with added lender risk.
A second mortgage is a mortgage that ranks behind the first mortgage on the same property. If the borrower defaults, the first mortgage lender is paid before the second mortgage lender.
Second mortgages are one of the most common forms of junior mortgage financing.
Second mortgages matter because they let homeowners borrow against built-up equity without replacing the existing first mortgage. That can be useful when the old mortgage has favorable terms the borrower wants to keep.
The tradeoff is that the second-lien lender takes more risk, so pricing and underwriting are usually tighter.
The lender looks at the property value, the balance of the first mortgage, the borrower’s cash flow, and the combined loan-to-value ratio before extending the new loan.
| Structure | Priority position | Typical borrower use | Risk to lender |
| — | — | — | — |
| First mortgage | Senior | Purchase or primary refinance | Lowest among mortgage liens |
| Second mortgage | Behind the first mortgage | Equity access without full refinance | Higher because recovery comes later |
| HELOC | Usually second-lien revolving credit | Flexible draw access | Similar second-lien risk, but with line usage uncertainty |
Common practical forms include Home Equity Loan and HELOC structures.
A homeowner owes $250,000 on a home worth $400,000 and does not want to refinance the old low-rate mortgage. The owner takes a smaller new loan secured by the remaining equity. That new loan is a second mortgage because it stands behind the original lien.
A second mortgage is specifically the next mortgage behind the first. A Junior Mortgage is the broader label for any subordinate mortgage, including second or third position.
If the new loan pays off and replaces the old mortgage, that is usually a refinance rather than a second mortgage.
First Mortgage: The senior mortgage that must be paid before the second mortgage.
Junior Mortgage: The broader category that includes second mortgages.
Home Equity Loan: A common fixed-balance second-mortgage structure.
Subordination: The legal ranking concept that explains why second mortgages are paid later.
Wraparound Mortgage: A different layered-property-financing structure that does not work like a normal second mortgage.