Vodafone, one of Britain's biggest companies, has been given a boost today after a positive assessment from the respected US business journal Barron's.The magazine argues that Vodafone is undervalued despite its sluggish performance in the last 12 months.The key issue is the firm's 45% stake in Verizon Wireless, the US mobile provider that is beginning to pay serious dividends ($4.5bn expected in 2012).Vodafone will be passing its portion of those payouts back to shareholders at a rate of $2 for a total 7.5% yield on its US stock listing. Significantly, the above may become an annual and recurring event, Barron's says, describing the first of those dividends as a potential 'watershed' event. Added to that is its strategic position in important emerging markets like Turkey and India and the tantalising prospect of a full blown merger with Verizon Communications (which owns 55% of Verizon Wireless). Barron's believes Newbury based Vodafone is a buy. At 2:59 GMT Vodafone was the fifth biggest riser on the FTSE, up 0.86% at 181.6p.BS