Vodafone's share price was boosted on Tuesday by an upgrade at by Nomura from 'neutral' to 'buy', saying that the proposed asset swaps with Liberty Global could lead to a "golden opportunity". The broker hiked its target price for the shares from 235p to 290p.Vodafone confirmed media speculation earlier this month that it is in the early stages of discussions with Liberty Global regarding a possible exchange of selected assets between the two companies.While the UK company assured that it is not in talks about a full merger of the two groups, Nomura reckons that asset swap discussions are "just the start" and could lead to wider negotiations."We think discussions around asset swaps will help to establish common ground around asset and synergy valuation, leaving the way for these sub-optimal scenarios to be weighed against a far more attractive scenario of combining all European assets under one roof," the broker said.Nomura has lifted its cost synergy target by 30% to $22bn and total synergy forecast to $32.6bn, after it conducted a "line-by-line analysis of the potential synergies for Vodafone and Liberty Global combining their assets in their three largest markets - the UK, Netherlands and Germany".The stock was up 0.9% at 241.5p by 10:13.