(ShareCast News) - Shares in engineering company Smiths Group surged after it emerged that US activist hedge fund ValueAct is a shareholder.According to the Financial Times, ValueAct's stake in Smiths is below the 5% required for disclosure to the London Stock Exchange.The news comes just days after it became clear that ValueAct has become the largest shareholder in London-listed aerospace and defence group Rolls-Royce.Smiths' shareholder register already includes Harris Associate and RWC as activist shareholders, with 7.4% and 1.4% stakes respectively, making ValueAct the the third, if confirmed, with a likely combined holding of over 10% by activists.At 1521 BST, Smiths shares were up 5.9% at 1,217p.