ROME/MILAN (Reuters) - A consortium led by Italian state lender CDP pledged on Wednesday to come up with a final offer to buy Atlantia’s 88% stake in a motorway business in 10 weeks, while repeating an initial valuation that Atlantia has signalled is insufficient.The negotiations are part of a long-standing wrangle over Autostrade per l’Italia after a bridge it ran collapsed in 2018, killing 43 people. The Italian government has repeatedly threatened to strip the motorway business of its operating licence, while Atlantia ATL.MI has sought to defend a key asset. In its latest proposal on Wednesday, CDP said the purchase of Atlantia’s stake in Autostrade would be carried out in stages and that it would update Atlantia on the asset’s valuation four weeks after the start of due diligence. The state lender, with co-investors Macquarie and Blackstone, valued the whole of Autostrade at 8.5 billion-9.5 billion euros ($10 billion-$11 billion) in an initial offer, sources told Reuters.