(Adds details) MILAN, Feb 23 (Reuters) - A consortium of investors led by Italian state lender Cassa Depositi e Prestiti (CDP) is expected to approve a binding offer for Atlantia’s 88% stake in motorway unit Autostrade per l’Italia on Tuesday, two sources close to the matter said. The bid will be based on a valuation of 9 billion euros ($11 billion) for 100% of Autostrade, the sources said. A previous non-binding proposal in December was pitched at a 8 billion euros valuation, one of the sources said. 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, one of the sources said. CDP and its investment fund partners Macquarie and Blackstone declined to comment. The consortium and infrastructure group Atlantia have been in talks over the sale of the Autostrade stake since last year. 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. “The offer has been improved since December and is based on a value for the whole of Autostrade of 9 billion euros,” one of the sources said. Atlantia, which is controlled by the Benetton family, will hold a board meeting on Friday to assess the offer. On Monday evening, CDP adjourned its board meeting decision to Tuesday to give time for Macquarie and Blackstone to get internal approvals for the detailed offer.