What do we call an agreement between two or more companies to share a business project?

An agreement between two or more companies to share a business project is known as a joint venture. This arrangement involves companies pooling their resources for a specific project or business activity while retaining their separate identities.

In a joint venture, the companies involved share both the risks and rewards associated with the project. This structure is particularly beneficial in situations where companies wish to leverage each other's expertise, capitalize on new market opportunities, or reduce the individual risk associated with the project.

While partnership and collaboration may also involve working together, they tend to refer to broader or different types of arrangements that may not involve a formal business project or shared ownership. A trade agreement typically concerns goods and services exchanged between countries rather than between companies for a specific project, distinguishing it from the concept of a joint venture.