Sustainable Growth. In the chapter, we used Rosengarten Corporation to demonstrate how to calculate EFN. The ROE for Rosengarten is about 7.3 percent, and the plowback ratio is about 67 percent. If you calculate the sustainable growth rate for Rosengarten, you will fi nd it is only 5.14 percent. In our calculation for EFN, we used a growth rate of 25 percent. Is this possible? ( Hint: Yes. How?)