The devil is in the details
As interest rates remain low, many issuers of debt (e.g. bonds, corporate notes, etc.) will look for possible ways of reducing their interest expenses. They may do this by executing call options and reissuing debt at lower rates. These lower rates will reflect the current market levels for the associated risk. Rather than continuing to pay high interest payments, it is to their benefit to pay off these debts and save money by issuing new instruments at the lower rates.