Have investment treaty arbitrators responded to the so-called ‘legitimacy crisis’ that has beleaguered the international investment regime in the past decade? There are strong rational choice and discursive-based reasons for thinking that arbitrators would be responsive to the prevailing ‘stakeholder mood.’ However, a competing set of legalistic and attitudinal factors may prevent arbitrators from bending towards the arc of enhanced sociological legitimation. This article draws upon a newly created investment treaty arbitration database to analyze the extent and causes of a shift in treaty-based arbitration outcomes. The evidence suggests that arbitrators are conditionally reflexive: sensitive to both negative and positive signals from states, especially vocal, influential and developed states.
