This paper analyses optimal irreversible investment policy when profits are subject to a multiplicative geometric Brownian motion shock. The marginal product of capital is increasing initially and decreasing thereafter. In the latter range, optimal policy is familiar: capacity is added gradually...

This paper analyses optimal irreversible investment policy when profits are subject to a multiplicative geometric Brownian motion shock. The marginal product of capital is increasing initially and decreasing thereafter. In the latter range, optimal policy is familiar: capacity is added gradually...