ISE Stock Indices have been created to measure the joint performances of group of stocks traded on the ISE. Some definitions and general rules crucial for the selection of the constituents and for the calculation of the ISE Stock Indices are as follows:

Market Value

Market value is calculated by multiplying total number of stocks that represent the capital by the stock price. In calculating the market value the prices of "old" and (if any) "new" stocks are considered separately. However, the price of the “old” stocks will be used for the “new” stocks which will not be traded separately and for the temporary shares which are created in the Central Registry Agency (CRA) during capital increases under the share capital system until the capital is registered and announced. 

Rate of Shares Outstanding

Rate of shares outstanding has been defined by the Capital Markets Board (CMB) as a concept showing free float rate of the stocks traded on the ISE stock markets, and is calculated and announced by CRA.

Market Value of Shares Outstanding

The Market Value of Shares Outstanding is calculated by multiplying the total market value by the rate of shares outstanding.

Lists A, B, and C

These are categories of lists which have been created to include stocks traded on the ISE markets according to the criteria determined by CMB and are subject to different trading principles and different measures.  

Corporate Governance Rating

Corporate governance rating means a rating of the conformity of a company with all the corporate governance principles as a whole, determined by a rating institution which is in the list of rating institutions authorized by CMB in the scope of the Communiqué of CMB on "Principles Governing Rating Activities in the Capital Market and Rating Institutions”.  

Foreign Exchange Rate

Refers to the Effective Buying Rates announced by the Central Bank of Republic of Turkey.

Price and Return Indices

ISE Stock Indices are calculated both in terms of Price and Return. The only difference between the Price Index and Return Index is related to the cash dividend payments. In cash dividend payments, the divisor of the Return Index is adjusted assuming that the dividend paid is invested in the stocks included in the index in proportion to the weight of the stocks, whilst the divisor of the Price index is not adjusted assuming that the dividend paid is excluded from the portfolio. 

Excluded Stocks

Stocks that are traded on the Watchlist Market and stocks included in list C are not included in any of the ISE Stock Indices.

Starting/Ending Index Calculation

In order to start calculating a new index except those indices which have a fixed number of stocks, the number of companies included in the scope of the index should reach 5. 
If the number of companies included in the scope of an index being calculated falls under 2, the calculation of the index is halted permanently effective from the first business day of the second month that succeeds the announcement to be made.

Appraisal Period

This is the period which the data used in the appraisal correspond to during the periodic review conducted with respect to the scope of the ISE 30, ISE 50, ISE 100 and ISE 10 Bank indices. The appraisal period includes the past 6 months from the last trading days of November, February, May and August for traded value, and the last trading day of November, February, May and August for market value. With regards to the rate of shares outstanding data, the most recent rates announced by CRA will be taken into account during the periodic review.

Appraisal Day

This is the date which the data used in the appraisal belong to during the periodic review conducted with respect to the scope of the ISE Dividend and ISE Dividend 25 indices.   Appraisal day is the last trading day of November and May for the market value data.  With regards to the rate of shares outstanding data,  the most recent rates announced by CRA will be taken into account during the periodic review. 

Index Period

This is the period in which the periodic changes in the scope of the ISE 30, ISE 50, ISE 100 and ISE 10 Bank indices will be in effect as a result of the periodic review conducted. There are 4 index periods, namely, January-March, April-June, July-September and October-December.

Announcement of Periodic Changes

Periodic changes on ISE 30, ISE 50, ISE 100 and ISE 10 Bank indices are announced at least 10 days prior to the beginning of the relevant index period. 

Index Calculation and Dissemination

Price Indices are calculated during the sessions once every 10 seconds and disseminated in real-time. Return Indices are calculated and disseminated once at the end of each session.

Data Accuracy