The prevailing investment treaty based rules regime institutionalises neoliberalism, which argues for a lesser involvement of the state in the market and a reduction in its economic functions. Despite neo-liberalism’s aversion to the role of the state in economic matters, the state is responsible for the public interest and is the highest authority. State measures should only qualify as in the public interest where the measure is introduced to address a specific problem and there is no policy overreach that could have been avoided to prevent the breach of a state’s obligations towards investors. Public interest regulation measures should only be introduced where there are no less restrictive measures of ensuring that international investment agreements obligations are not violated. The public interest regulation theory places as much emphasis on the substantive outcome as on the procedural method of arriving at the outcome.