he article examines the problem of excess in cases of plurality of persons within absolute civil legal relationships. The authors proceed from the assumption that, where a legal good is jointly held, internal relations between the participants of such plurality do not always remain irrelevant to external legal relationships. Special attention is given to situations in which one participant performs a legally significant act concerning the common object while acting both in his or her own interest and in the common interest. Using co-ownership and co-authorship as examples, the article analyzes the limits of permissible independent conduct by a participant in plurality, the criteria for normal and excessive conduct, and the legal consequences of acting beyond the agreed or presumed common will. The authors argue that excess in plurality reveals the external effect of an internal legal relationship and should be assessed through the principles of good faith, reasonableness, fairness, and balance of interests.