Papua New Guinea is an independent, sovereign state—not owned by any other country, corporation, or entity.
It gained independence from Australia on September 16, 1975, becoming a member of the Commonwealth of Nations. The head of state is the British monarch (represented by a Governor-General), but political power rests with the elected Prime Minister and Parliament.
PNG governs its own territory, resources, and foreign relations. While it receives aid and investment from nations like Australia, China, and the U.S., its sovereignty is internationally recognized and constitutionally entrenched.