Retention ratio

The share of earnings kept in the business, equal to one minus the payout ratio.

The company paying out 73.2% retains 26.8%.

Multiplied by return on equity it gives the sustainable growth rate, which is the growth the company can fund from its own earnings. A firm retaining 26.8% at an 18.6% return on equity can grow about 5% a year internally.

Growth beyond that needs external money, and the model should say where it comes from.