In the United States, rapid social change has led to shifts in both purpose and organizational forms of actors within the social economy. A diverse array of organizations, companies, constitute the social economy, including for-profit businesses, 501(c)(3) non-profits, cooperatives, credit unions, limited liability companies, social enterprises, and benefit corporations. Those which do not fit neatly into the aforementioned categories may be considered a hybrid organization. Some scholars define hybrids as organizations that maintain a social mission while pursuing profit, but others define them more specifically as for-profit ventures that operate to generate revenues for a partner nonprofit. Hybrids have primarily existed in sectors such as job training, health care, and microcredit, but have recently expanded to include environmentalism, technology, and even consulting. Organizational differences are acknowledged in the tax codes of several states with entities such as benefit corporations.