Founded in 1990, Operis is a specialized professional services firm dedicated to project finance. The company provides expert advisory services for large-scale infrastructure and energy projects globally. Its core offerings include financial modelling and model auditing, transaction advisory, valuations, due diligence, and financial modelling training. Operis also develops and sells its own proprietary software, OAK (Operis Analysis Kit), which is an add-in for Microsoft Excel designed to enhance the quality and efficiency of financial models.