WOSL was set up by New Zealand’s four main oil companies and is now owned by BP, Mobil, Z Energy and Z Energy 2015 (formerly Chevron). The WOSL Board is made up of one director for each shareholder, and the chair rotates annually. All decisions require a unanimous vote. Mobil, BP and Z Energy are the largest shareholders with 28% each. Z Energy (2015) is the smallest shareholder, with a 16% stake.

The shareholders own the Wiri Terminal land on which WOSL operates. WOSL manages the site and assets, which are owned by Refining New Zealand. The Marsden Point Terminal has a slightly different structure. The land there is owned by Refining New Zealand, while the shareholders provide the assets. WOSL manages the site.