Investor participation is an important element for sustainable Stock markets. Sustainable stock market participation can allows sustainable funds for companies, for their investment and national economic development. In some developing countries low investor participation is an important problem. Thus the aim of the paper is to find out main factors affect the investor participation in Turkish Stock Market. Monthly and Quarterly Data covers from 2003 to 2022 has been used for this aim. By the Correlation analysis it has been revealed that the relationship between investor numbers and macroeconomic data. Lee Strazicich LM unit root test show that break point of the time series of the investor numbers. There are main two factors affect investor numbers in Türkiye (Turkey). One of them is 2008 global financial crisis and another one is 2018 new local macroeconomic policy in Türkiye. Findings show that the country has not yet sustainable policies for stable participants in stock market.