DEFINITION of 'Weighted Average Maturity  WAM'
The weighted average of the time until all maturities on mortgages in a mortgagebacked security (MBS). The higher the weighted average to maturity, the longer the mortgages in the security have until maturity. Also known as "average effective maturity".
INVESTOPEDIA EXPLAINS 'Weighted Average Maturity  WAM'
The measure is calculated by totaling each mortgage value represented by the MBS. The weights of each mortgage is found by dividing the value of each into the total of all. To arrive at the WAM number the weight of each security is multiplied by the time until maturity of each mortgage, and then all the values are added together. For example say an MBS has three mortgages valued at $1,000, $2,000 and $3,000 (a total of $6,000) and mature in one, two and three years respectively. The weights of these are 1/6 (1,000/6,000), 1/3 (2,000/6,000) and 1/2 (3,000/6,000). The WAM is 2 1/3 years (1/6 x 1 year + 1/3 x 2 years + 1/2 x 3 years).

Mortgage
A debt instrument, secured by the collateral of specified real ... 
Weighted Average Remaining Term ...
The remaining life of an assetbacked security or a mortgagebacked ... 
Commercial MortgageBacked Securities ...
A type of mortgagebacked security that is secured by the loan ... 
MortgageBacked Security (MBS)
A type of assetbacked security that is secured by a mortgage ... 
Dwarf
A slang term used to describe a pool of mortgage backed securities ... 
PassThrough Security
A pool of fixedincome securities backed by a package of assets. ...

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