MILAN (Reuters) - Cassa Depositi e Prestiti (CDP) on Tuesday gave the go-ahead to submit an offer to buy Atlantia’s 88% stake in Autostrade per l’Italia unit, CDP said, after two sources told Reuters the bid would value 100% of Autostrade 9 billion euros. Italian state lender CDP, which will file its binding bid with its investment fund partners Macquarie and Blackstone, did not disclose the financial details of the bid due to be presented by Wednesday. CDP said the consortium could purchase up to 100% of Autostrade if the motorway company’s minority shareholders - Germany’s Allianz and funds DIF, EDF Invest and China’s Silk Road Fund - exercise their right to sell their 12% under the same conditions that will be accepted by Atlantia. A previous non-binding bid for Autostrade in December was pitched at an 8 billion-euro valuation, one of the sources said. “The offer has been improved since December and is based on a value for the whole of Autostrade of 9 billion euros,” the source said. Barring last-minute surprises, the offer is not likely to include conditions protecting the buyers from the legal risks linked to the deadly collapse in 2018 of a bridge run by Autostrade, the source said. The negotiations are part of an effort to end a political dispute over Autostrade’s motorway concession triggered by the bridge disaster, which killed 43 people on Aug. 14, 2018. CDP unit CDP Equity will hold the 51% of the vehicle that will acquire the stake, with Macquarie and Blackstone holding 24.5% each, CDP said in the statement. The CDP unit will have the option to sell part of its shares to other institutional investors. Atlantia, which is controlled by the Benetton family, will hold a board meeting on Friday to assess the offer and could decide to call a shareholders’ meeting to vote on the proposal if it deems it interesting. As an alternative, Atlantia’s board may reject it and press on with a plan to demerge the motorway unit from the group, betting on a better offer in the coming months. Minority investors in Atlantia, including hedge fund TCI, have criticized the involvement of CDP in the sale of the unit, adding the value of Autostrade is more than 12 billion euros. A government change in Italy, with a new cross-party ruling coalition headed by former European Central Bank Chief Mario Draghi, could also have an impact on the strategy of state lender CDP and its plans for Autostrade. ($1 = 0.8226 euro)