adsFor investors entering Africa’s biggest share offering, getting the number of shares right may be the easiest part of the investment decision and one of the easiest places to make a costly mistake.

The Dangote Petroleum Refinery IPO is being sold as an opportunity for ordinary Nigerians to own a piece of one of Africa’s most ambitious industrial projects. But before investors worry about the refinery’s valuation, profits or expansion plans, there is a more basic question to get right: how many shares can their money actually buy?

The offer price is N525 per share, with a minimum subscription of 10 shares. More importantly for investors putting larger sums to work, the offer terms provide for “multiples of 10 Offer Shares thereafter.” In other words, an investor cannot simply divide a budget by N525 and submit the resulting number if it is not a multiple of 10.

That distinction is small on paper but potentially significant for retail investors. Take N1 million. Dividing N1 million by N525 gives 1,904.76 shares. An investor cannot apply for 1,904.76 shares, nor should the figure simply be rounded to 1,905. The nearest eligible application below the budget is 1,900 shares, costing N997,500.