This paper examines the impact of the evolving relationship between public economic law and commercial law on the contemporary identity of public economic law. The analysis is based on the institution of the State Treasury and the regulatory reform of the exercise of the State Treasury’s ownership rights introduced in 2016. It is argued that the legislator abandoned the model of direct statutory interference with commercial law institutions in favour of regulations addressed to public authorities exercising the State Treasury’s ownership rights. This shift reflects a broader transformation of the regulatory model, moving the focus of public economic law from direct intervention in private-law relationships to the regulation of the State’s own economic activity. The paper advances the thesis that this evolution has implications extending beyond the institution of the State Treasury. It demonstrates a gradual redefinition of the identity of public economic law, which is increasingly shaped by its economic subject matter and its function of organising the State’s participation in the economy, rather than by the administrative-law methods traditionally associated with this branch of law.