In response to the weakness of traditional efficiency assessment methods taking risk into account, the modification of the Certainty Equivalent method is proposed in this paper. The possibility of connecting solutions from different fields provides for the elaboration of a more effective tool to illustrate and indicate the accurate level of risk in the investment efficiency calculus, which is the matter under consideration in the paper. The authors propose to use the modified method of a Certainty Equivalent that is based on fuzzy numbers. The aim of the method is to make decisions that are less incorrect. The work should be treated as an introduction to proposed further research on the subject.