The OECD has published a tax working-paper, Carbon pricing design; effectiveness, efficiency, and feasibility; an investment perspective. The paper considers how the design of carbon pricing instruments affects their effectiveness, efficiency and feasibility. The paper discusses how volatile carbon prices can cause risk-averse investors to forego clean investment that they would have undertaken with more stable prices. It also evaluates the effectiveness and efficiency of policy instruments to stabilise carbon prices in Emission Trading Systems.