In the world of finance, there exists a concept known as a bond indenture. This refers to an agreement between a borrower and a lender, outlining the terms and conditions of a bond. One important requirement specified in this agreement is the annual retirement of a certain portion of the debt. This means that the borrower is obligated to repay a predetermined amount of the bond each year. This ensures a gradual reduction of the debt and helps the firm manage its financial obligations effectively.