“…The problem of the optimal financing of the firm can be formulated as an optimal control problem. The formulations, such as those of Davis (1970), Krouse (1972), and Krouse and Lee (1973), permit the firm to finance its investments by retained earnings, debt, and/or external equity in various proportions which may vary over time. Note that earnings not retained are paid out as dividends to the firm's stockholders.…”