Several market-based trading programs currently operate in New York State (NYS) to address various environmental problems. Because these programs rely on market mechanisms to achieve efficient and economical emissions reductions, they are often referred to as market-based programs. With each of these programs operating in overlapping jurisdictions and with different certification protocols and definitions of the commodity/attribute being traded, however, markets can become balkanized and fail to function properly. Lack of precision and homogeneity in the underlying commodity leads to less efficient markets and works to society’s disadvantage by diminishing our ability to attain environmental and energy goals. To address this potential problem, this report provides a systematic review of these market-based environmental programs, both mandatory and voluntary, in current use or in the advanced stages of development, and examines the relationships and interactions among them. The following four trading platforms are discussed: (1) Acid Rain/NYS Acid Deposition Reduction Program; (2) Clean Air Interstate Rule (CAIR)/Clean Air Transport Rule (CATR); (3) New York Renewable Portfolio Standard (RPS); and (4) Regional Greenhouse Gas Initiative (RGGI). The following three trading currencies are also discussed: (1) Emission Reduction Credits (ERCs); (2) Emission Allowances (EAs); and (3) Renewable Energy Credits (RECs). Where applicable, this review considers voluntary greenhouse gas credit markets; clean energy set-asides in emission allowance programs, and the use of emission reduction credits as offsets for non-attainment pollutants under the NYS New Source Review (NSR) air permitting program.