The aim of the article is to compare the effects of mergers and acquisitions carried out by entities from developed and emerging countries. The article covers consolidation transactions completed between 2000 and 2018, exclusively by listed automotive companies. 764 consolidation transactions extracted from the Thomson Reuters Eikon database were observed, for which an efficiency measurement method based on the relationship of the share price to the stock market index was adopted. Data analysis was carried out using descriptive statistics and statistical inference methods. A comparison of the efficiency of M&As completed in developed and emerging countries showed no significant differences in a statistical sense. This means that the macroeconomic conditions of the country from which the company originates have no significant impact on the chances of success of the consolidation implemented by the company. Companies from emerging countries were found to be more profitable, with higher liquidity and were less indebted. On the other hand, entities from developed countries had better operating efficiency ratios, suggesting that they achieved higher margins. The study thus also contradicts the thesis that cost position is important for the efficiency of entities, especially in emerging countries. In the context of the results of the comparison between the two groups of companies, it is reasonable to assume that the determinants of consolidation success are microeconomic in nature and are independent of the country in which the transaction takes place.