Il costo del capitale proprio: un modello di stima del premio per i rischi specifici

The present study proposes a new, unified evaluation approach aimed at enclosing in a single model a number of economic theories for estimating the cost of equity considering also unsystematic risks. Our objective is extending the CAPM by defining a standard formula for quantifying the premium for certain idiosyncratic risks as a function of a set of firm-specific quantitative information. We define two innovative econometric models, for listed and non-listed firms respectively, which consider five idiosyncratic risk factors: firm size, market expectations, operating risks, financial structure and stock market price volatility. The models were tested on a sample of European non-financial listed companies. The empirical results show that while the CAPM systematically underestimates the cost of equity, the proposed models correctly estimate its expected value; furthermore, they show a slight improvement also in terms of estimates’ volatility. Due to their efficacy and ease of use, the proposed models represent a valid practical tool for investors, analysts and professional evaluators. This work contributes to the existing literature by proposing and testing original models for estimating the unsystematic risks’ spread to be included in the cost of equity on the basis of a set of firm-specific accounting and market information.