An indispensable premise for the economic development of joint-stock companies is getting sufficient equity capital to ensure their prestige on the capital market and to gain investors’ confidence in the strategic development prospects. At present, the economic aspect of the joint stock companies’ equity capital has not been analysed sufficiently and thoroughly, neither in the national, nor in the international specialty literature. In this context, this article considers various approaches to the economic content of the concept of equity, as well as the theoretical and scientific analysis of the definitions (perspectives) and their functions. The research carried out identified and studied 5 groups of characteristics related to the essence (meaning) of equity; additionally a scientific foundation for the notion of “equity of the joint-stock company” has been laid down. Aditionally, the main reason of this article is linked with economical development of joint-stock company in the Republic of Moldova.