The work is devoted to the study of the legal nature of the trust in the conditions of the mixed Soviet economy of the 20s of the 20th century with the dominance of state property. It is established that the organizational and legal structure of the business association, which the trust acted as, fit into the new system of the national economy that arose during the period of the new economic policy and was subsequently transformed into various kinds of national economic sectoral and inter-sectoral complexes. As a result of the study, the author comes to the conclusion that the previously established organizational and legal forms of business associations can be quite successfully adapted to new historical realities.