The fourth sector is a concept that refers to the emergence of a new approach to economy and enterprise that combines the best of the public sector (governments), private sector (for-profit businesses), and third sector (non-profits). This fourth sector is characterized by a focus on societal and environmental concerns, and it is made up of organizations and networks that are dedicated to reimagining and remaking systems of finance, enterprise, measurement, policy, production, consumption, and more to better serve the common good.

In the quinary sector of the economy, which refers to the highest level of the knowledge-based economy that is driven by research, innovation, and technology, the fourth sector plays a key role in driving economic growth and development. The fourth sector is characterized by a focus on innovation and entrepreneurship, and it is responsible for developing and commercializing new products and services that address social and environmental challenges.

The fourth sector in the quinary sector is typically made up of a wide range of organizations, including social enterprises, impact investors, and venture philanthropists. These organizations are funded through a variety of sources, including grants, donations, and investments, and they operate in a wide range of fields, including healthcare, education, environment, and human rights.

Overall, the fourth sector plays a key role in the quinary sector, as it drives innovation and entrepreneurship, and focuses on addressing social and environmental challenges. It is an important component of the knowledge-based economy and is critical to the long-term growth and development of the quinary sector.