The Averch–Johnson effect is the tendency of regulated companies to engage in excessive amounts of capital accumulation in order to expand the volume of their profits. If companies' profits to capital ratio is regulated at a certain percentage then there is a strong incentive for companies to over-invest in order to increase profits overall. This investment goes beyond any optimal efficiency point for capital that the company may have calculated as higher profit is almost always desired over and above efficiency. [1]
Excessive capital accumulation under rate-of-return regulation is informally known as gold plating. [2]
But the so-called Averch-Johnson effect of overcapitalization does not as a general case involve "gold-plating". [3]
Suppose that a regulated firm wishes to maximize its profit:where is the revenue function, is the firm's capital stock, is the firm's labor stock, is the wage rate, and is the cost of capital. The firm's profit is constrained such that:where is the allowable rate of return. Assume that . We may then form a functional to find the firm's optimal action:where is the Lagrange multiplier (also known as the shadow price). The derivatives of this functional are:Taken together, this implies that:The ratio of the marginal product of capital and the marginal product of labor is:Since this new cost of capital is perceived to be less than the market cost of capital, the firm will tend to overinvest in capital. [4]
The Black–Scholes or Black–Scholes–Merton model is a mathematical model for the dynamics of a financial market containing derivative investment instruments. From the parabolic partial differential equation in the model, known as the Black–Scholes equation, one can deduce the Black–Scholes formula, which gives a theoretical estimate of the price of European-style options and shows that the option has a unique price given the risk of the security and its expected return. The equation and model are named after economists Fischer Black and Myron Scholes. Robert C. Merton, who first wrote an academic paper on the subject, is sometimes also credited.
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