Nigerian banks and investment firms are signing up investors across Africa while seeking regulatory approvals for arrangements designed to broaden access to Dangote Petroleum Refinery and Petrochemicals FZE’s share offering. United Capital Plc, FSDH Capital Ltd and First Cap Ltd. are among the firms wooing investors and approaching regulators and stock exchanges across the continent to act as intermediaries for investors. The $1.6 billion initial public offering, the biggest ever on the continent, opened in Nigeria this week and is also intended to be offered to investors across Africa, subject to approval in each market.

United Capital has received approval to market the offer in countries where it operates, including Rwanda, Ethiopia and Ivory Coast, spokesman Babatunde Adenuga said. The firm plans to aggregate orders from investors in those markets and subscribe to the IPO on their behalf through its nominee business. Under such an arrangement, a nominee holds the shares as the registered owner on behalf of the underlying investors, who retain the economic interest in them.

United Capital will subscribe as a “bulk entity” for registered investors and allocate their respective holdings after the IPO allotment, Adenuga said. FSDH Capital has also invited investors outside Nigeria to apply for shares in the offering, which will be processed through its nominee unit, according to an emailed note. Aliko Dangote, Africa’s richest person and owner of the refinery, has said he is keen for investors from across the continent to buy shares in the IPO.

The offering opened on Sept. 14 and is due to close on Oct. 13. Dangote plans to issue an additional 30% of the shares for sale if it is oversubscribed.