Balance-weighted measure of how long loans in a mortgage pool have been outstanding.
Weighted average loan age, often called WALA, is a balance-weighted measure of how long the loans in a mortgage pool have been outstanding.
WALA matters because loan age can affect how investors think about prepayment behavior. Newly originated loans, seasoned loans, and older loans may have different payoff patterns.
For borrowers, the term helps explain how ordinary time in a mortgage becomes a pool-level characteristic. A borrower may simply know when the loan closed. The MBS market summarizes many loan ages into a single measure.
Borrowers usually do not see WALA while applying for or closing a loan. The term appears after origination in MBS pool reporting and investor analysis.
It becomes useful when explaining why mortgage pools are described not only by rate and maturity, but also by how seasoned the loans are.
| Loan-age idea | Why it matters |
|---|---|
| Newly originated loans | May still be near the start of their payment history |
| Seasoned loans | Have already survived some early payoff or refinance behavior |
| Older loans | May have different remaining balances and refinance incentives |
A pool contains loans that closed at different times. The weighted average loan age summarizes how old the pool’s loans are, with larger remaining balances carrying more weight than smaller balances.
WALA differs from Weighted Average Maturity because WALA looks backward at loan age, while WAM looks forward at remaining scheduled maturity.
It also differs from Pool Factor. Pool factor shows how much original principal remains. WALA shows the balance-weighted age of the loans.
It also differs from Prepayment Risk. Prepayment risk is the uncertainty about early payoff behavior, while WALA is a descriptive input investors may consider when thinking about that behavior.