History and Methodology


The roots of Türkiye’s Top 500 Industrial Enterprises survey goes back to the 1960s. It was first released as the “Top 100 Enterprises” in 1968 and then the number of enterprises rose to 300 enterprises in 1978 and to 500 enterprises in 1981.

In 1991, another study was prepared and announced with the title “325 Industrial Enterprises following The Top 500 Industrial Enterprises”. This additional study continued as “250 Industrial Enterprises following The Top 500 Industrial Enterprises” between 1992 and 1997 and later this numbered rose to 500 in 1998. So, since 1998, the data belonging to Türkiye’s Top 1000 Industrial Enterprises are disclosed to the public every year.

As a mirror reflecting Türkiye’s economic outlook, “Türkiye’s Top 500 Industrial Enterprises” surveys serve as a reference for many academic and scientific studies.



The main objective of the “Türkiye’s Top 500 Industrial Enterprises (ISO 500)” survey is to determine the largest enterprises engaged in the industry in Türkiye, identify their aggregates, thus revealing the development of Turkish industry and helping draw a road map for the future.

“Türkiye’s Top 500 Industrial Enterprises” is a survey-based study. Participation in the survey is on a voluntary basis.

The survey covers Türkiye as geographical unit and includes all enterprises in industrial sector.

Türkiye’s Top 500 Industrial Enterprises Survey is carried out via the “Survey User Login” application at www.iso500.org.tr. Enterprises that do not have carried out these procedures in time are not included in the survey.

The survey asks for information about net sales, production-based sales, exports (in USD), profit/loss for the periodbefore tax, earnings before interest, tax, depreciation and amortization (EBITDA), total assets and liabilities, annual average number of employees, R&D expenditures, and factor income payments through which gross value-added is calculated (salaries and wages paid, interest paid, non-operating revenues, amortization and indirect taxes paid, provisions allocated from profit). The participants are also asked to provide their capital distribution and economic activity code (NACE Rev. 2).

The survey is based on the statements of enterprises. However, in order to verify the accuracy of the data, the enterprises are also requested to upload their Corporate Income Tax Return (e-return), which includes accumulatedbalance sheets and income statements prepared according to the Tax Procedure Law (TPL) to be submitted to the Ministry of Finance.

The survey data is benchmarked with the e-return data, and in case of any inconsistency, enterprises are asked to make corrections and/or submit additional documents and/or e-return data are taken into account.

As the “Türkiye’s Top 500 Industrial Enterprises” survey aims to determine the largest industrial enterprises in Türkiye, it also includes enterprises that do not wish to disclose their data. Data for such companies is used in all assessments, even though it is not publicly disclosed.

The “Türkiye’s Top 500 Industrial Enterprises” covers the industrial sectors of mining and quarrying, manufacturing, and electricity production, and is based on the criterion of production-based sales (net). Production-based sales (net) include the sale of goods manufactured by the enterprise, and goods that are bought and sold directly as they are are excluded.

Although the main ranking criterion is production-based sales, enterprises are also ranked according to their net sales, gross value added tax, equity, total assets, profit/loss for the period (before tax), earnings before interest, tax, depreciation and amortization (EBITDA), export and average number of employees.

The survey uses the Statistical Classification of Economic Activities in the European Community (NACE Rev.2) for sectoral classification.