Aliko Dangote’s oil refinery has locked down $2.5 billion from a private share sale that ranks as the largest disclosed primary equity placement on the continent, setting up a public listing that bankers expect to be Africa’s biggest ever.

Dangote Petroleum Refinery and Petrochemicals FZE said Thursday it had completed the placement at 3.7 times oversubscription, issuing and allotting the new equity to a mix of sovereign-linked funds, development finance institutions and long-time strategic backers. Africa Finance Corporation and India Infra Buildco, a vehicle arranged through the African Export-Import Bank, were among the participants, alongside a broader pool of institutional and individual investors.

The raise is the first time the 650,000-barrel-a-day refinery has brought in outside capital beyond its founding shareholder base, a shift that people close to the transaction said reflects Dangote’s push to widen ownership before an initial public offering targeted for as early as September on the Nigerian Exchange, sources familiar with the matter said.

The success of the private placement gives a rare glimpse into the size of capital available to Nigeria if there were large and bankable projects.