biostudies-literatureUnknown12(112)Zambrano EThe distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper, we show that a thermodynamic model based on the maximum entropy principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive database of Spanish firms, which covers, to a very large extent, Spain's economic activity, with a total of 1,155,142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of economic system for creating/destroying firms, and that can be used to measure the health of a capitalist-based economy. Indeed, oJournal of the Royal Society, Interface20150789https://www.ebi.ac.uk/biostudies/studies/S-EPMC4685849biostudies-literatureThermodynamics of firms' growth.PMC4685849Zambrano EPlastino AHernando AFernandez Bariviera AHernando RfalseThermodynamics of firms' growth.The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper, we show that a thermodynamic model based on the maximum entropy principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive database of Spanish firms, which covers, to a very large extent, Spain's economic activity, with a total of 1,155,142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of economic system for creating/destroying firms, and that can be used to measure the health of a capitalist-based economy. Indeed, o2015-01-01T00:00:00Z2015 Nov2026-05-05T07:11:27.314Z2019-03-26T22:40:28ZS-EPMC46858492651082810.1098/rsif.2015.0789