Informational (in)efficiency of the Polish Stock Exchange

The aim of this study is to determine whether (and to what extent) the weak form of efficient-market hypothesis could be considered true in relation to the financial instruments listed on the Warsaw Stock Exchange in relation to the exchanges of Baltic Sea countries. With respect to the analyzed indices three types of randomness tests were performed: autocorrelation test, series test and unit root test. The direct practical implication of this paper is the assumption that the selected active investment strategies can be successfully used for some groups of shares quoted on WSE, as well as for selected European exchanges.