The platform dependency index as a tool for assessing the vulnerability of small businesses in collaboration with marketplaces

The problem of platform dependence of small businesses in the context of trade digitalization is considered. Modern marketplaces (Wildberries, Ozon, etc.) provide small businesses with opportunities to quickly scale sales and reduce barriers to market entry, however, a new form of economic dependence on digital platforms is emerging. Based on the analysis of current theoretical approaches and existing practices of platform interaction, an integral indicator has been developed and proposed for practical application - the platform dependency index (PDI), reflecting the ratio between the share of platform sales, platform costs and gross profit of the enterprise. In the course of an empirical study, PDI was tested on a sample of 30 small business entities engaged in trading activities through marketplaces. The values of the PDI in the context of product categories (clothing, textiles, cosmetics, children's goods, food) are estimated. It has been established that more than 50% of enterprises in highly competitive sectors have a critical level of dependence when the PDI value is more than 100%, which means a complete or almost complete loss of gross profit in favor of platforms. At the same time, companies with diversified sales channels demonstrated a significantly lower level of dependence. The results obtained allow us to recommend the PDI as an analytical tool for assessing digital vulnerability and forming strategies for the sustainable development of small businesses. The hypothesis of heterogeneous dependence by product segments is confirmed, which requires the adaptation of microeconomic models of enterprise behavior in a fee-based economy.