Cost of Debt Cost of Debt is the required rate of return on investment of the lenders of a company. Pn=∑ j=1 (1+k。y k1=ka(1-T) 15-615-6 Cost of Debt is the required rate of return on investment of the lenders of a company. ki = kd ( 1 - T ) Cost of Debt P0 = I j + Pj (1 + kd )  j n j =1