We study the issuance and payout policy that maximizes the value of a firm facing both agency costs of free cash-flow and external financing costs. We find that firms have target cash levels and optimally issue equity when they run out of cash. We characterize the process modelling the number of outstanding shares and the dynamics of the stock prices. In line with the leverage effect identified by Black (1976), we show that both the volatility of stock returns and the dollar volatility of stock prices increase after a negative shock on stock prices.