The article presents detailed regulations related to opportunities for limiting the accumulation of the function of a supervisory board member of a joint-stock company in other entities. They are mainly related to persons who perform public functions and to companies with the share of the State Treasury. The author emphasises that the binding regulations lack a general principle that would ban a joint-stock company supervisory board member from being appointed to the board of another company within the same capital group. He also indicates consequences that such practices have for their performance.