Multi-authoring has been gaining popularity since the foundation of academic publishers. Today we observe a global trend in favor of multi-authoring. On the other hand, in certain domains, such as CERN collaborations in physics, multi-authoring has a different connotation than other domains. The number of co-authors may be above 5000, an all-time record in the history of academic publishing. CERN collaborations have been accomplishing one of the most significant achievements in physics, as well; therefore, the collaborations produce highly cited articles. Highly cited, multi-authored articles have influenced university rankings in the past decade, due to the distribution of the citations per affiliated institution. In the present study, we analyze the influence of multi-authored articles on ranking methodologies. Our findings reveal that the presence of multi-authored CERN articles have a significant impact on all bibliometric ranking indicators, and consequently on the ranking positions of the institutions worldwide.