In one of the biggest upheaval in the corporate sector, the Tata Sons Board has appointed Ratan Tata as the interim chairman of the group, replacing Cyrus Mistry. The decision was taken at a Board meeting today. Mistry has resigned from his post as chairman. The Board has constituted a Selection Committee to choose a new Chairman. The Committee comprises Ratan N. Tata, Venu Srinivasan, Amit Chandra, Ronen Sen and Lord Kumar Bhattacharyya, as per the criteria in the Articles of Association of Tata Sons. The committee has been mandated to complete the selection process in four months. Ratan Tata had been chairman from 1991 till his retirement on December 28, 2012. Ratan Tata had also been the chairman of the major Tata companies, including Tata Motors, Tata Steel, Tata Consultancy Services, Tata Power, Tata Global Beverages, Tata Chemicals, Indian Hotels and Tata Teleservices. During his tenure, the group\u2019s revenues grew manifold, totalling over $100 billion in 2011-12. Cyrus Mistry had in December 2012 become the sixth chairman of the Tata Group, replacing Ratan Tata. Mistry had been the director of the company since 2006. Mistry was earlier managing director of the Shapoorji Pallonji Group. He graduated with a degree in civil engineering from Imperial College, London, UK, in 1990. In 1997, he received an MSc in management from the London Business School. 48-year old Mistry had last month described his experience since taking over as chairman of the Tata group. "When I assumed office as the group chairman, I was acutely aware of a few things. I knew I was not leading a single company, but was at the helm of a unique institution with a rich and glorious history. I was very conscious that we had a powerful foundation that had been nurtured over the last fifteen decades, and we now needed to build the capabilities that would allow us to succeed for the next 150 years." [jwplayer 2lsbuOgi] Mistry had said that there is an ongoing focus on performance management systems and the quality of the strategies deployed by operating companies. "Several measures have been taken towards this end, including reinforcing the need for performance and having clarity of strategy," he had said. More details about Mistry's resignation and Tata's appointment are awaited.