The amended bid sees Telefónica offer €8.55 billion for E-Plus – an improvement on the original €8.1 billion, which Slim claimed was too low – with KPN taking on a 20.5% stake in the merged company, instead of the initially agreed 17.6%.
Telefónica will also decrease its final share in the combined E-Plus and Telefónica Deutschland company from 65% to 62.1%.
América Móvil owns 30% of KPN and the company said on Monday that it agreed to support the deal, as well as confirming that its takeover bid for KPN still stands.
According to the Financial Times, this lays to rest rumours that Slim made the bid in attempt to obtain a better offer for E-Plus from Telefónica.
KPN shareholders are due to vote on the sale of E-Plus on October 2 2013, and the deal is still awaiting regulatory approval.
Negotiations for América Móvil’s KPN bid are likely to begin in September and run for at least eight weeks.