The economic crisis has forced managers of joint stock companies to look for short-term solutions for the sharp changes in stock prices of their companies. Even the companies of the V4 countries are not the exception. The authors have focused on those companies where have been used either reverse stock split or stock split. They analyzed the effects of the reverse stock split or stock splits on the abnormal returns of stocks. In this paper, the authors analyzed a dataset from 1993 until 2015 with 124 reverse stock splits and 184 stock splits in total focused on the stock market in V4. Based on their own research they conclude that when reverse stock splits were used stock returns significantly decreased one day around the announcement date. They conclude that managers of a company might use this instrument to move the stock price back to the optimal trading range outside of the penny stock area. In the case of stock splits, the authors concluded that the use of this tool results in a significant increase in the returns of a stock after the announcement date. However, the results are in contrast to some former studies which found no positive effect on the returns caused by stock splits. The authors conclude that managers of a company might use this instrument to transport information content of future (positive) performance of a company to the traders. Keywords: Vysegrad group countries, normal stock split, reverse stock split, abnormal returns. JEL Classification: G11, G23, G32