Telefónica, the Spanish telecoms company, has shunned investment banking advisers for its $5.85bn (€4.73bn) acquisition of BellSouth's South American mobile phone units, relying instead on its in-house mergers and acquisitions team.

Telefónica declined to provide further details, but potential advisers have missed out on an estimated $25m of advisory fees, based on the minimum 0.5% charge of the deal price.