8.8%. If the credit rating of debentures is downgraded by any rating agency from A+, the coupon rate will be increased by 0.25%. If the credit rating of debentures is downgraded by any rating agency from A, the coupon rate will be increased by 0.75%. If the credit rating of debentures is upgraded by any rating agency from below A+, the coupon rate will be decreased by 0.25% for every notch of upgrade until it reaches A+. If the credit rating of debentures is upgraded by any rating agency from A+ to AA-, the coupon rate will be decreased by 0.50% for every notch of upgrade until it reaches AA-. If the credit rating of debentures is upgraded by any rating agency from AA- to AA, the coupon rate will be decreased by 0.25% for every notch of upgrade until it reaches AA.