What is the role and purpose of the corporation?

The concept of the corporation originated through governmental charter allowing individuals to carry on business collectively. Basically, the charter gave the corporate entity form legal status that was similar to personhood. The concept of the corporation as a legal person has expanded over time to the point that corporations enjoy many of the same constitutional protections as US citizens.

The corporate entity also allows individuals to have a beneficial interest without being actively involved in business operations. That is, it allows for increased division and transfer of ownership interest in a business activity. It allows for the utilization of outside capital from investors (rather than just debt or capital contributions from founders) to grow business operations. The active trading of ownership in corporate entities gave rise to the formation of US stock exchanges and the private equities market.