Millicom's board of directors has said that Atlas Investissement's improved takeover bid still undervalues the company.

The latest bid of around $4.4 billion was announced last week by French billionaire Xavier Niel’s Atlas Investissement.

It was an increase from the company's initial bid of $4.1bn, which was rejected after Millicom's board of directors deemed it too low.

Atlas, which is Niel's investment vehicle, already owns a 29 percent stake in Millicom.

It noted in an open letter to shareholders that it increased its bid from $24 per share to $25.75.

However, in response to this bid on August 9, Millicom has once again urged its shareholders to reject the offer.

"The independent committee is of the unanimous opinion that the revised offers continue to significantly undervalue Millicom and recommends that shareholders and SDR holders not accept the offers," said the Millicom board of directors in a statement.

Millicom operates as Tigo across several Latin American markets, serving close to around 50 million mobile customers.

Atlas is the biggest stakeholder in the telco, first scooping a seven percent stake back in 2022.