Betting on Biology: Rethinking Probability as the Currency of Risk in Biotechnology Portfolios.

Uncertainty is an integral facet to the biotechnology and life sciences industry. From early target drug discovery to regulatory approval and commercialization, investment decisions are made under conditions of incomplete knowledge and asymmetric information. Indices of probability, particularly probability of technical and regulatory success, probability of clinical success, and risk-adjusted net present value, have become foundational tools for structuring these uncertainties within portfolio decision-making frameworks. However, their interpretation and application often lack conceptual precision and contextual nuance. This commentary examines the use of probability indices in describing and managing portfolio risk in biotechnology and life sciences. It reflects on their role in assigning risk to new drug targets, novel therapeutic modalities, and stage-specific development programs.