Rate Trigger

What Does Rate Trigger Mean?
A sizeable decline in interest rates that may trigger or cause companies to call in bonds that otherwise pay high coupon or interest rates. Because these bonds are being called before their initial expiration date, theoretically, bondholders can expect to receive a premium or additional sum for their securities.

Investopedia explains Rate Trigger
As an example, if a company that issues bonds containing a coupon or interest rate of 12% was to see the prevailing interest rate to drop to 7%, it may exercise its option to "call", or buy back these bonds from the debt holders, enabling the company to borrow money at a much lower rate than when the security was first issued. The company, however, must pay bondholders a premium, or an additional amount over and above the bond’s par value in order to repurchase the debt. The fluctuation in interest rates acted as the trigger for such an action.