Answer:
Additional premium is 3%
Explanation:
Without debt the shareholders' rate is computed thus:
Ke=Rf+beta*(Mrp-Rf)
Ke=4.5%+1.0*(5%)
Ke=9.50%
With debt financing added to the capital structure, the equity beta changes to 1.6,the shareholders' expected return is computed thus:
Ke=4.5%+1.6*(5%)
Ke=12.5%
The additional premium required is the increase in expected return of 3%(12.5%-9.5%)
The 3% is to compensate the equity shareholders for taking the risk of getting little or no dividends at all because the debt-holders interest must be paid first