Weighted Average Maturity (WAM) 

The weighted average number of months to the final payment of each loan backing a mortgage security, weighted by the size of the principal loan balances. Also known as weighted average remaining maturity (WARM) and weighted average remaining term (WART).

Remarks: Bond funds including mutual funds (open-end and closed-end, actively managed and indexed), exchange-traded funds and unit investment trusts offer a convenient and affordable way to invest in a diversified portfolio of bonds, but a bond fund investment can differ from a bond investment in ways that are important to understand.