Spanish online outlet Okdiario quoted unidentified sources close to the operation saying Goldman Sachs was advising Cellnex, while Morgan Stanley was advising American Tower and Brookfield.

Cellnex, Brookfield, American Tower and their advisers declined to comment.

Cellnex shares were up 8.3% at 12.21 GMT to lead gains in Spain's blue chip index Ibex-35.

The shares over the past year are down almost 40%.

Barcelona-based Cellnex this month said CEO Tobias Martinez would step down after the company in November announced a strategy shift away from acquisitions to focus on lowering debt.

After borrowing heavily to build the largest cellphone mast network in Europe, mainly through acquisitions, it has adopted a "more conservative financial risk profile" in the face of rising interest rates.

(Reporting by Andres Gonzalez and Emma Pinedo; additional reporting by Jesús Aguado; editing by Jason Neely)