APX Blackrock Apex Municipal Fund,

SAO PAULO--Private-equity firms Apax Partners LLP and Bain Capital LLC have joined forces and made a binding offer to buy PT Portugal from its Brazilian owner Oi SA (OIBR).

The offer values the assets at an enterprise value of 7.07 billion euros ($8.8 billion) on a cash and debt free basis, Oi said in a statement on Wednesday.

"The target assets do not include PT Portugal's investments in Africa, debt of PT Portugal, or its investments in Rio Forte Investments S.A.," Oi said.

The private equity firms offer is slightly higher than the offer made by Luxembourg-based Altice SA (ATC.AE), earlier this month, which evaluated the same assets at EUR7.03 billion.

-Write to Rogerio Jelmayer at rogerio.jelmayer@wsj.com

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