During the 20th century, academic financial economists widely accepted the market efficiency hypothesis. Almost everyone has said that the stock markets and the securities market react very effectively to any new information in the market. It has been argued that when information regarding market influencing factors emerges, it spreads like wildfire in the market and stock prices adjust accordingly without delay. This means that neither the fundamental analysis related to the analysis of the company's financial information such as profits, share capital, etc. is performed. nor technical analysis linked to the analysis of the historical performance of the company's shares allows the investor, experienced or not, to obtain a return. beyond the average market return by holding any stock portfolio with average market risk. A random walk and efficient market hypothesis are associated because the random walk is a term often used in the financial literature which holds that subsequent price variation in stocks are independent of any pattern based on the historical trend of price variation . The logic behind the idea of ​​random walk is that the change in price of a stock during one trading session is based on the information available in the market and the change in price during the next trading session is independent of the price change of the previous session due to the reason that the price change the next day reflects the impact of the information they have. It is also important to note that, given the idea of ​​the random walk, information is unpredictable and therefore the movement of the stock price is also unpredictable. This means that the change in stock price during a trading session fully reflects the impact...... middle of paper ......n Wall Street (New York: WW Norton & Co., 1973, 1st edition )––––––– “Returns of Equity Mutual Fund Investments from 1971 to 1991,” Journal of Finance, 50, 549-72. (1995) _______ Review of Irrational Exuberance by Robert J. Shiller, in Wall Street Journal, April 4, 2000. Miller, Merton, Financial Innovations and Market Volatility (Blackwell: Cambridge, 1991) Nicholson, SF (1960), “Price-Earnings Ratios,” Financial Analysts Journal, July/August, 43-50. (1960) Odean, Terrance “Do Investors Trade Too Much? » American Economic Review, 89, 1279-1298. (1999)Poterba, James and Lawrence Summers “Mean Reversion in Stock Returns: Evidence and Implications”, Journal of Financial Economics, 22, 27-60. (1988) Rasches, Michael “Massively Confused Investors Making Blatantly Ignorant Choices (MCI-MCIC)”, Journal of Finance, 56:5, 1911-1927. (2001)