Index Maintenance plays a crucial role in ensuring stability of the Index as well as in meeting its objective of being a consistent benchmark of the equity markets.

IISL has constituted an Index Policy Committee, which is involved in policy and guidelines for managing the CNX Indices. The Index Maintenance Sub-committee takes all decisions on addition/ deletion of companies in any Index.

The maintenance of the S&P CNX Nifty and the CNX Nifty Junior are synchronised so that the two indices will always be disjoint sets; i.e. a stock will never appear in both indices at the same time. Hence it is always meaningful to pool the S&P CNX Nifty and the CNX Nifty Junior into a composite 100 stock index or portfolio.

The index is reviewed every six months (on half-yearly basis) and a six weeks’ notice is given to the market before making changes to the index set.