India-based Bharti Airtel increased its stake in Robi Axiata for an undisclosed sum as the Bangladesh operator prepares to list its shares on the local exchange to raise funds for a planned network expansion.

In a stock market filing, Bharti Airtel said its subsidiary Bharti International (Singapore) acquired an additional 6.3 per cent interest in Bangladesh’s second-largest operator by subscribers to take its holdings to 31.3 per cent. It acquired the stake from NTT Docomo.

Malaysia-based Axiata Group holds the remaining 68.7 per cent.

Robi applied to conduct an IPO in early March.

In the filing, Bharti Airtel said it purchased the shares from NTT Docomo at a mutually agreed valuation. The transaction requires approval from the Bangladesh Telecommunication Regulatory Commission.

Bharti Airtel merged its Bangladesh unit with Robi in November 2016. At the time, Airtel had less than a 7 per cent market share in the country and was the fourth-largest of eight players.