AVERAGE LIFE

Summary

Average Life is a measure that tells you, on average, how long it will take to get back the principal (original investment amount) from a bond or other debt security. It's calculated by taking all the expected principal payments over time, weighing them by their size, and finding the average timing. Think of it like asking 'If I buy this bond today, when can I expect to get most of my original money back?' This is particularly important for bonds that pay back principal gradually over time rather than all at once at maturity.

Usage Context

Understanding average life is crucial when analyzing fixed-income securities, particularly asset-backed securities, mortgage-backed securities, and any bonds with amortizing principal payments. It helps investors assess cash flow timing and compare securities with different repayment structures.

Common Confusions

• Confusing average life with duration (duration measures price sensitivity to interest rate changes)
• Thinking average life is the same as maturity date (maturity is when the security officially ends)
• Assuming all payments are weighted equally (larger payments have more influence on the average)
• Believing average life is fixed (it can change if prepayment patterns change)