The maturity date is the expiration date of a financial instrument — the day when the principal amount must be repaid in full. Whether it is a bond, fixed deposit, loan, or certificate of deposit, every debt instrument has a maturity date.
Example: You buy a 10-year US Treasury bond on January 1, 2025. The maturity date is January 1, 2035. On that day, the government returns your full principal ($10,000) along with the final interest payment. Until then, you receive regular coupon payments.
Maturity dates determine an instrument's risk profile. Short-term (under 1 year) instruments like Treasury bills carry less risk. Long-term (10-30 years) bonds carry more risk because interest rates and inflation can change dramatically over decades. The yield curve plots interest rates across different maturities.