Tidjane Thiam an executive director, sitting on the plc board. In January 2007, after Richard Harvey announced he would step down as chief executive of Aviva, Thiam was tipped as a possible future head of the group. Thiam left Aviva in September 2007 to become chief financial officer of Prudential plc. In March 2009, Thiam was named chief executive, effective from October, after Mark Tucker chose to step down. The appointment made him the first African to lead a FTSE 100 listed company. His departure from the role was announced on 10 March 2015. After he became chief executive, Prudential launched a
FTSE 100 Index "Financial Times" and the London Stock Exchange. It is calculated in real time and published every second when the market is open. The FTSE 100 broadly consists of the largest 100 qualifying UK companies by full market value. Many of these are internationally focused companies, however, so the index's movements are a fairly weak indicator of how the UK economy is faring and are significantly affected by the exchange rates of the Pound. A better indication of the UK economy is the FTSE 250 Index, as it contains a smaller proportion of international companies. FTSE 100 companies represent about 81%