Financial markets change continuously: markets increase and decrease in relative size, companies are listed, delisted, taken over and restructured, and securities produce cash flows. An important challenge for an index provider is to record the evolution of markets in a consistent and transparent way.
In this paper we describe how an index provider manages these complex processes of change, with a specific focus on equity indexes. We explain how an index’s constituent list of stocks is selected and maintained, how the index review process works and how indexes deal with corporate actions. We also cover index governance: how an index firm ensures that its benchmarks are constructed consistently, objectively and according to high technical standards.