Saudi Telecom Co. and French telecom billionaire Xavier Niel’s Iliad SA are among suitors that have progressed in the bidding for Altice’s Portuguese assets, according to people with knowledge of the matter.

Warburg Pincus — which has teamed up with buyout firm Zeno Partners and former Credit Suisse Group AG Chairman António Horta-Osório — has also been invited to the second round of bidding, the people said. Several private equity firms that had initially looked at the business, including Apollo Global Management Inc. and CVC Capital Partners, are no longer in the running, the people said.