This final thesis is based on an in-depth analysis of financial instruments related to environmental, social and governance (ESG) objectives. There is a special focus on green, social, sustainable and sustainability-related bonds. This research is particularly relevant in the context of new regulations and the appearance of these instruments in Croatia. The characteristics and objectives of each type of bond are defined, following the principles of the International Capital Market Association. Included is an overview of the use of sustainable securities in the world and a case study on bonds related to sustainability, issued by the Meritus Group to provide a concrete example in Croatia. The aim of the paper is to emphasize the importance of understanding the distinct characteristics and objectives of each type of ESG bond to support sustainable financing and the transition to a low-carbon economy. The most used method when writing is the compilation method. Along with it, the methods of classification, description, comparison and analysis were also used.