The ability to call bonds away from investors is of particular value to the issuer when:

When interest rates decline significantly below the coupon interest rates on outstanding bonds, it becomes advantageous for the issuer to call those bonds. This is because the issuer can replace higher-interest debt with new bonds that have lower interest rates, thereby reducing their overall debt service costs.

When the market interest rates fall, the issuer of the bonds can take advantage of this situation by exercising the call option. By calling the bonds, the issuer pays off the existing bonds at face value and reissues new bonds at the new lower interest rates. This strategy results in lower interest expenses over time, making it a financially beneficial decision for the issuer.

In contrast, if interest rates rise or stabilize, calling the bonds would not be to the issuer's advantage, as they would have to refinance at a higher cost, thereby negating any benefits associated with calling the bonds. Fluctuating interest rates without a significant downward trend would also not create a compelling scenario for calling bonds. The specific situation of declining interest rates presents the most valuable opportunity for issuers to improve their financial positioning through callable bonds.