In November 2004, following a period of turmoil caused by the revelation that Shell had been overstating its oil reserves, it was announced that the Shell Group would move to a single capital structure, creating a new parent company to be named Royal Dutch Shell plc, with its primary listing on the London Stock Exchange, a secondary listing on the Amsterdam Stock Exchange, its headquarters and tax residency in The Hague, Netherlands and its registered office in London. What was the cause of the period of turmoil prior to the announcement that the Shell Group would move to a single capital structure?