This paper investigates the effect of the firm life cycle on the cost of equity capital. To test the hypothesis we use mean difference test of cost of equity capital and regression model (ordinary least squares method). The sample includes 586 firms – year observation about firms listed in Tehran Stock Exchange, during the period of 1384 to1393. The mean difference test shows that cost of equity is higher in the decline stage than growth and mature stages. Also using Dickinson’s life cycle (2011) measure reveals that decline stage of firm life cycle is positively associated with cost of equity, while the growth and mature stages of the life cycle are negatively associated with many estimates of the cost of equity. Therefore, relationship between decline, growth and mature stages of the firm life cycle and cost of equity resembling U-shaped pattern.
