This talk will explore issues of proof of corruption in international arbitration, both commercial and investor-state, with a particular focus on the so-called “red flag” analysis (sometimes also referred to as faisceaux d’indices). What are red flags and what function should they play in the analysis and assessment of anti-corruption risks? To what extent are they “evidence” or simply risk indicators that must be explored and confirmed in order to find corrupt practices? What is the effect of multiple red flags on the analysis? This talk will examine the use and limitations of red flags, drawing from recent decisions of arbitral tribunal such as Metal-Tech v. Uzbekistan and Spentex v. Uzbekistan, as well as commercial cases.