In the area of access to finance for Small and Medium sized Enterprises (SMEs) there are often market imperfections/failures – either as temporary effects or as fundamental structural deficiencies. To identify and analyze these issues, SME Access to Finance Market Assessments (AFMAs) are essential. The purpose of such an assessment is to identify and, if and where possible, quantify the market failures or suboptimal investment situations, and investment needs. This text provides guiding principles and typical approaches for AFMAs from the authors’ perspective.