India’s biggest mobile carrier Bharti Airtel Ltd has chosen UBS, JP Morgan and Citi to coordinate the London initial public offering of its Africa business, two sources familiar with the matter said.

In February Bharti Airtel Ltd said the holding company for its Africa operations was looking at a potential IPO. The appointment of banks for a London listing is a sign the process is progressing.

Bharti Airtel and the banks declined to comment. The company has not given a timeframe for the listing to happen.

The sources declined to comment on the valuation of the Africa operations but the business represents just over a quarter of the revenue of the listed entity, which has a $20 billion market capitalisation.

Bharti Airtel owns telecom assets in 14 African countries. In the quarter ending June 2018, Africa revenue was 201 billion Indian rupees ($2.80 billion) and earnings before interest, tax, depreciation and amortisation (EBITDA) were 68 billion rupees.

Globally the company has almost 460 million customers. In the quarter ending June 2018, it posted revenue of $3 billion with EBITDA of more than $1 billion. ($1 = 71.7900 Indian rupees)