The rapid institutional changes taking place today, including the emergence and global spread of new institutions bring to the fore the question of how new institutions develop. From the 1990s onwards, a new technical term has begun to spread in the literature: institutional entrepreneurship, reflecting the revaluation of people’s activity in institutional change. The aim of the paper is to answer the questions regarding this kind of entrepreneurship. How does institutional entrepreneurship emerge, how can we interpret and define this phenomenon? What kind of driving forces are behind it? How does it work in the real economy? The novelty of the paper is in addressing institutional entrepreneurship as the result of a special ability and activity of actors to combine different, already known elements for building up new institutions. The study introduces the characteristics of institutional entrepreneurship, using the example of the sharing economy, by contrasting sharing as an alternative to conventional market solutions. The paper also demonstrates how the institutional entrepreneurship of sharing changes its socio-economic environment, from mobilization of unused resources through perception of ownership to the increase of the growth potential of the economy.