What Is the BIST 100 Index?

Borsa Istanbul uses the BIST 100 as the main index of its equity market. It is made up of 100 shares selected from the companies traded on its Star Market, and it automatically covers the shares of the BIST 30 and BIST 50 indices. The selection pool consists of shares that have traded for a minimum period, and the Star Market list is complemented with additional shares when it is too short to fill the index.

Shares are ranked twice: by average free-float market value and by daily average traded value over the review period. A final ranking is built by combining the two lists, and the highest-ranked shares enter the index. Weights follow free-float market value, the market value of the shares available to the public, and the index divisor is adjusted for capital increases and changes of membership, and in the return version also for cash dividends, so that the series stays continuous.

Borsa Istanbul calculates its share indices in Turkish lira, US dollars and euros, in a price version and a return version; the only difference between the two is the treatment of cash dividends. Membership is reviewed for each quarter of the calendar year, and changes are announced in advance. The index value is a number of points that depends on the base date and base value of the series; it says nothing about the lira price of a single share.