PRIME Coalition and NYSERDA – along with many other government agencies, investors, and philanthropists – share a common interest in supporting early-stage (Pre-Seed through Series A) companies that promise dramatic reductions in global greenhouse gas emissions. In some cases, investors aspire to use the potential climate impact of a new venture as part of their decision-making process about whether or not to invest. For many organizations, climate impact assessment is also important after making an investment for reporting purposes. However, despite the importance of, and interest in, guiding investments to early-stage ventures with large potential climate impact, early-stage investors today lack a common lexicon with which to discuss the potential climate impacts of early-stage companies. Furthermore, early-stage investors do not employ standard methodologies for assessing the potential climate impact of a new venture and the technologies, solutions, or business models they are looking to bring to market. Today’s climate impact assessment tools and services are designed exclusively to retrospectively assess the climate impact of a business as it exists today. For earlystage businesses with small operations and limited or no product deployment, these tools and services do not provide actionable insights. There is a gap in the marketplace for tools that can inform investors about the potential for their investments to mitigate future emissions. In an attempt to help fill this gap, PRIME partnered with NYSERDA, New York State’s energy innovation agency, to develop a methodology for assessing the potential climate impact of early-stage ventures. The ultimate goal of this project is to help early-stage (Seed and Series A) investors allocate capital to new ventures that promise climate change mitigation at large scale. This report makes three primary contributions toward this goal. Specifically, this report: 1) Highlights the need for actionable climate impact tools for early-stage investors, and introduces Emissions Reduction Potential as the metric required for early-stage investors to make better informed investment decisions based on the potential climate impact of a new venture; 2) Defines a methodology for down selection – a process for narrowing from many companies to a smaller subset of potential investment targets – based on potential climate impact; and 3) Develops a methodology for estimating the Emissions Reduction Potential of a new venture. Peter Drucker – the famous management scholar – stated that “you can’t manage what you can’t measure.” We review the landscape of existing climate impact assessment and find that existing tools – while powerful and highly impactful for well-established late-stage and public companies – do not provide early-stage investors with the information needed to manage their climate impact investments. We thus introduce a new metric – Emissions Reduction Potential – that describes a venture’s ability to mitigate future emissions.