Taxonomies have become a key tool for implementing government climate policies by classifying activities based on their role in achieving net-zero emissions by 2050. According to Climate Bond, by 2023, more than 40 countries and regions have a taxonomy or are in the process of developing one. Globally, most green taxonomies exclude fossil fuel activities, while mixed taxonomies, which include transitional components, allow limited fossil gas power generation with strict emission and time constraints. Thailand’s Taxonomy, the first science-based transitional taxonomy, was adopted in May 2023 and uses a traffic light system to classify activities based on their alignment with the Paris Agreement. While fossil gas is temporarily used to support renewable energy in countries like the US, China, and Germany, they aim for a medium-term reduction in hydrocarbon consumption. Recent studies highlight significant fugitive emissions from fossil gas, prompting stricter policies and lifecycle emissions assessments. This chapter focuses on sustainable finance investments in different regions of the world. North America primarily the United States and Canada are prominent players in the sustainable finance market. Europe is a leader in responsible investing.