adjective
proprietary
pruh-PRY-uh-tair-ee/prəˈpraɪəteri/
Held under the exclusive control of an owner.
The company keeps its proprietary manufacturing process secret from competitors.

Etymology
The ownership element marks something as belonging to a particular owner. In this sense, that private ownership carries control over whether others may use it.
In context
Exceptional proprietary resources just means they use their own banks research which isn't necessarily better than any independent source.
More examples
- We need a license to use this proprietary software.
- The agreement prevents employees from sharing proprietary data.
- He speaks about the shared garden with a proprietary air.
Forms
proprietor noun — A person who owns a business.