MILAN, Aug 28 (Reuters) - Infrastructure fund Macquarie is preparing a binding offer for Enel's ENEI 50% stake in broadband joint venture Open Fiber, Italian daily Il Sole 24 Ore said on Friday.
The offer, which should be presented by early-September, would value Open Fiber 7.7 billion euros ($9.1 billion), including debt.
Macquarie approached Enel in June with an initial offer for its stake in Open Fiber, which is jointly controlled with Italy's state lender CDP, and talks between the two companies had been extended.
($1 = 0.8431 euros)
(Reporting by Giulio Piovaccari, editing by Giselda Vagnoni)