Question 3: The information efficiency of stock markets is one of the widely debated topics in financial management theory and has been the subject of numerous scientific studies in recent decades. There is a combination of popularity, controversy, and criticism that may indicate that the idea of ​​interaction between information and stock prices has multiple values. What does an efficient market mean? In a fully efficient market, the current value of the security share is always equal to the value of the investment (a fair price), which is evaluated by a large number of well-informed and highly professional market analysts. There are some “perfect market” terms. A large number of investors - sellers and buyers, as a result a single transaction does not affect the market as a whole. All information is completely and freely available to everyone. The lack of additional costs results in the payment of transactions, taxes or market membership fees. The expectations of all market participants regarding economic indices and expected outcomes are the same. There is, however, one observation on the above stated, all these conditions cannot be fully implemented in a real market: the information is not free, there are taxes and overheads, investors can have a different name (e.g. short or long-term strategies). The basic theory describing market information efficiency is the efficient markets hypothesis (EMH). Information is efficiently classified based on how quickly and accurately stock prices react to new information, so that no one is able to earn abnormal returns. All information can be divided into three types: past information, publicly available information and all information. According to Fama c...... half of the paper ......without the stock markets. In particular, G. Soros suggests that recent developments on the stock markets have demonstrated the inadequacy of the EMH. Furthermore, Warren Buffett, who had made his fortune during the crisis of the 1970s, soon had the same point of view to make the case that the market is not efficient. These opinions deserve attention, at least the authors achieved a practical result: they earned money. In conclusion, a stock indicator is a very complicated "machinery" that includes an infinite mix of ever-changing factors. It would be presumptuous to draw unequivocal conclusions about the efficiency of information when there are too many controversial and contrived arguments. However, despite the evidence supporting efficiency, the anomalies detected could be considered contradictory to the EMH and these anomalous effects could undermine the efficient market theory.