Twitter's shares have lost over 10% of their value this week as efforts to replace its old boss, Dick Costolo, continues.
Mr Costolo's resignation announcement in early June came alongside a statement saying that Twitter's co-founder, Jack Dorsey, would replace him but that such a move would only be 'temporary'.
In the months preceding his departure, Mr Costolo had come under increasing investor scrutiny, with shares in the company falling by almost a third in the two months before he resigned.