Repayment of debt. The most common method of retiring corporate debt is to set aside money each year in a Sinking Fund.
Most municipal bonds and some corporates are issued in serial form, meaning different portions of an issue-called series-are retired at different times, usually on an annual or semiannual schedule.
Sinking fund bonds and serial bonds are not classes of bonds, just methods of retiring them that are adaptable to debentures, convertibles, and so on. See also Refunding.


