https://www.reuters.com/article/us-telecom-italia-elliott-stake-report/activist-elliott-takes-telecom-italia-stake-to-shake-up-governance-strategy-idUSKCN1GI0ZI >Activist investor Elliott Advisors has built a stake in Telecom Italia (TIM) (TIM), it said on Tuesday, in a move that could challenge the way top investor Vivendi runs Italy's biggest phone group.