Airtel Money, the mobile-money arm of Airtel Africa (LSE: AAF; NGX: AIRTELAFRI), has formally announced its intention to list in London through a secondary share offering that will raise no new capital for the company.

A source familiar with the matter told Reuters that the offering could raise about $800mn, implying a market capitalisation of roughly $8bn-$9bn for Airtel Money.

"London has not had a $1 billion-plus IPO since 2021, so the deal would undoubtedly be a positive for the exchange," ​the news agency quoted Samuel Kerr at M&A analytics platform Mergermarket as saying.

The IPO will consist of existing Airtel Money shareholders selling shares to new investors. Airtel Money itself will not issue new shares or receive any proceeds from the offer.

Airtel Africa currently owns about 77.85% of Airtel Money, with other shareholders holding the remaining 22.15%. Airtel Africa plans to remain a long-term shareholder after the IPO, but the company has not yet disclosed which existing shareholders will sell, how many shares each will offer or Airtel Africa's resulting post-IPO stake.

The company has said at least 10% of Airtel Money's shares are expected to qualify as free float after the listing. That threshold refers to the proportion of shares counted as being in public hands under London listing rules; it does not mean that exactly 10% of the company will be sold in the IPO.

Airtel has not yet confirmed the offer size, valuation or final number of shares to be sold. Indicative pricing and further offer details are expected in early October, with final pricing targeted for mid-October.

The International Finance Corporation has agreed to buy up to GBP67.2mn ($90mn) of shares at the final offer price as a cornerstone investor.

IntelliNews reported in July that Airtel Money had selected London after an earlier first-half flotation was postponed because of market volatility. Market estimates at the time centred on a valuation of about $10bn and a share sale of $1.5bn-$2bn, broadly in line with the $10bn valuation used by CLSA in June.

By mid-September, reported expectations had been revised lower. People familiar with the transaction were cited as putting the prospective valuation at about $8bn-$9bn and the share sale at roughly $800mn following investor feedback. Airtel Africa shares fell more than 11% on September 18 after the revised terms were reported.

Those figures remain market estimates rather than confirmed IPO terms. An $800mn offering would make it London's largest IPO since 2021, according to Mergermarket.

Airtel Money’s customer base increased 23.3% year on year to 56.5mn in the three months ended June 30. Quarterly revenue rose 38.9% to $404mn, while earnings before interest, tax, depreciation and amortisation increased 29.3% to $198mn.

The platform processed transactions with an annualised value of more than $245bn, up 51.5% from a year earlier. Transaction value per customer increased 13% to $371 a month as Airtel expanded merchant payments, transfers, savings, lending and other financial services.

East Africa remained Airtel Money’s largest region, with 41.7mn customers and quarterly revenue of $297mn. Francophone Africa contributed 11.4mn customers and $102mn in revenue, while the newer Nigerian operation had 3.4mn customers and generated $5mn.

A successful listing would give investors direct exposure to Africa’s expanding mobile money market and allow Airtel Africa to realise part of the value built in the division while retaining a controlling interest.

Airtel Africa, which operates in 14 African countries, reported a 31% year-on-year rise in first-quarter revenue as customer growth, higher data usage and currency appreciation boosted its results.

The company is present in Nigeria, Kenya, Malawi, Rwanda, Tanzania, Uganda, Zambia, Chad, the Democratic Republic of the Congo, Gabon, Madagascar, Niger, the Republic of the Congo, and the Seychelles.

Airtel Africa has been listed in London and Lagos since 2019.