The weighted-average loan age ( WALA ) measure is used in pools of mortgage-backed securities That olefins the average number of months since the date of origination of notes of all the loans in a pool weighted by remaining principal balance .  In the calculation each loan is in proportion to its total aggregate of the pool. 
The measure is often used by organizations buying or selling securitized mortgages , like Fannie Mae in United States. It helps investors estimate the amount of time before the whole pool is repaid. This number will fluctuate as mortgages in the pool are paid off. The main counterpart to the weighted average maturity is the Weighted Average Maturity rate.
- Jump up^ Taff, Laurence G. (2003). Investing in Mortgage Securities . p. 142.
- Jump up^ Hunkar Ozyasar. “How to Calculate Weighted Averages for Loan Maturity” . Retrieved May 31, 2017 .