We have developed a stress testing approach to determine the boundary values of indicators of the economic state of backbone non-financial enterprises when managing them according to the criterion of the cash balance. One of the principal indicators affected by the pandemic is considered – the change in the company’s revenue. The formulation and method of determining the permissible change in revenue at which the enterprise will maintain normal functioning are proposed. As a condition for normal functioning, the nonnegativity of the company’s cash balance projected for the next year is assumed. From this condition, the permissible change in revenue is determined based on the obtained analytical expression and data from open sources, making it possible to reduce the complexity of determining the boundary values of the indicator. We analyzed the actual data for 2020 and compared it with the calculated results. We propose to use the concept of stress testing to select government-supported enterprises in a pandemic. Keywords — stress testing, the critical combination of parameters, risk management, financial forecasting, modeling, inverse problem, cash flow, operational efficiency, COVID-19