The article discusses the use of business activity indicators, based on data from the monthly monitoring of enterprises conducted by the Bank of Russia. It considers the indicators of the business climate, divided into large enterprises and small and medium-sized businesses, as these play an important role in the market economy and are more sensitive to crises but also more adaptive than larger businesses. Small and medium-sized business activity indices are in high demand among the business community, so the article focuses on this group of enterprises. General formulas for calculating the business climate indicator are provided by the Bank of Russia. Seasonally smoothed indicators of the business climate were analyzed and compared separately for large businesses and a group including small and medium-sized enterprises. Indicators were compared separately for small and medium enterprises, as well as within industries of small and medium businesses. The response of different groups and industries to economic changes, such as crises and structural transformations, was revealed. The business climate indicator for small and medium-sized companies was compared with the RSBI Support of Russia index. An alternative index was also created using the RSBI methodology, using monitoring data from the Bank of Russia. All calculated indices were compared, the level of correlation was checked, and they were compared with statistical data on small and medium enterprise turnover growth. The article explored the potential of using enterprise data to monitor and analyze the economy.