MasMovil's board had agreed in June on a $3 billion offer from KKR, Providence and Cinven and described it as beneficial for the company, which has taken market share from bigger rivals in Spain's fiercely competitive telecoms market.
The board also said that some shareholders had complained the consortium of KKR, Providence and Cinven were offering too little.
MasMovil said one board member, Rafael Dominguez, who holds 8.25% of the company, considers the offer price is too low and plans to vote against it.
MasMovil set up a team to look for competing offers with the help of Goldman Sachs but said it received no firm expressions of interest from anyone who might launch a higher bid or any "strategic alternatives."
Minority shareholder Polygon said in June the terms of the bid, which included a commitment to sell from holders of 30% of MasMovil's stock, made any competing bid impossible.
Spain's market regulator approved the bid last month.
MasMovil said senior Providence executive John Hahn, who sits on MasMovil's board by virtue of his fund's 9% stake in the company, declared a conflict of interest and abstained from all discussions and votes on the matter.
(Reporting by Isla Binnie. Editing by Jane Merriman)
By Isla Binnie