What's the converse of a subcontractor?

My understanding of contractors and clients is something like:

Party 1
   |
   V
Party 2
   |
   V
Party 3

Legend:
  "->": "employs"

From the perspective of Party 1:

• Party 2 is a contractor
• Party 3 is a subcontractor

From the perspective of Party 2:

• Party 1 is a client
• Party 3 is a contractor

From the perspective of Party 3:

• Party 1 is a ???
• Party 2 is a client

What is Party 1 to Party 3? Is there an accepted word like "superclient" that Party 3 can use to refer to Party 1?

In the case of building work, Party 1 might be called the "property owner". In other contexts they might be called the "end customer".

Additionally, and again in a construction context, Party 2 is (at least in the US) called the "general contractor". Outside the construction field, they can be called the "primary contractor".