Abstract
One of the main investment instruments that attract foreign and domestic investors is the stocks of companies. The Istanbul Stock Exchange, which has been serving more than 300 companies with a volume of billions of dollars since 1985, offers various opportunities to international investors. Of course, investors have to apply to many analyzes of companies and companies in order to evaluate these opportunities correctly and to make a profit. Therefore, it is of great importance for millions of investors around the world that firm and market data are highly transparent, consistent and predictable. Because otherwise, markets that cannot show stability in developing countries cause the market values of the company to rise and fall excessively with the opportunities and crises that constantly occur. This situation leads to unnoticeable manipulations in firm and market values and investors to be mistaken due to the inability to analyze them correctly. The purpose of this research is to estimate the market values of 2019 Borsa Istanbul firms by using the Artificial Neural Networks (ANN) method with the data of Forbes 2000 companies in 2019. As a result of the analysis, it was revealed that the companies in Borsa Istanbul have higher or lower market values than they should be, and the results are also supported by the comparisons of ratio analysis.