EN
The purpose of this paper was to determine the nature of the relationship between multinationality and performance (M-P relationship) among Polish companies. It is based on a sample of over 300 Polish companies listed on Warsaw Stock Exchange, studied over two years (625 observations were used for statistical processing). Multiple regression and t-statistic analyses were applied to test three hypotheses. The dependent variable was company performance and the independent variable was the degree of company internationalization. A number of control variables were also incorporated in the regression models. The statistically significant results of the multiple regression analyses show that Polish companies experience a negative linear relationship between their degree of internationalization and performance for two variants of the dependent variable, and a non-linear, U-shaped relationship for one dependent variable. The results also show that companies operating on international markets achieve lower market-valuation results than their domestic counterparts, and companies with lower levels of multinationality perform better than those with higher levels of multinationality