Display of calculated index values in a foreign currency
With a view of enabling meaningful comparison of the performances of stock exchanges of various countries or alternative investment instruments, end-of-session closing values of all ISE Price and Return Stock Indices are displayed on USD and EURO basis and announced on the Turkish and English versions of the ISE website on a daily basis.

The following formula is used in the calculation of indices in foreign currencies:

EY_t = [(E_t / K_t) / (E_b / K_b)] * EY_b

E_t = Index closing value on day “t” 
K_t = Foreign exchange rate on day “t”
E_b = Closing value on the initial date of the index
K_b = Foreign exchange rate on the initial date of the index
EY_t = The value of the index in foreign currency at period t
EY_b = The initial value of the index in foreign currency