A non-linear change process is a specific feature of a poorly regulated market economy. However, many researchers have shown that different economic sectors do not respond to market cycles in a similar way. Regional economic systems are a combination of many sectors, therefore a hypothesis about the correlation between the stability of regional economies and market cycles is examined. The study is conducted using the Baltic countries (hereinafter referred to as Greater Baltic Region, GBR) as an example. GBR countries have been classified into highly stable, relatively stable, unstable, and highly unstable based on the study of the stability of national economies to global cycle processes. The GDP dynamics of the countries were compared to GDP cycles of the US and the EU, which are the main financial centres. To understand the reasons, the sectoral structure of GDP is additionally considered. The results allow the author to classify of GBR countries according to the structure of economic sectors and the stability of the regional economy.