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 of the entire market capitalisation of the London Stock Exchange. Even though the FTSE All-Share Index is more comprehensive, the FTSE 100 is by far the most widely used UK stock market indicator. Other related indices are the FTSE 250 Index (which includes the next largest 250 companies after the FTSE 100), the FTSE 350 Index (which is the aggregation of the FTSE 100 and 250), FTSE SmallCap Index and the FTSE Fledgling Index. The FTSE All-Share aggregates the FTSE 100, FTSE 250 and FTSE SmallCap. Component companies must meet a number of requirements set out by the FTSE Group,