The occupation of Zuccotti Park in Wall Street, New York, in 2011 brought economic inequality to the forefront of political debates, framing it as the ‘the 99% versus the 1%’. Soon after, Thomas Piketty’s Capital became an unexpected editorial success. Bringing together work on the history of economic measurement with the study of political conflict and mobilisation, this chapter looks at why the topic of inequality became politicised at this particular time and why was it framed in terms of the difference between the 1% and the rest. It argues that the production of ‘inequality knowledge’ in the language of economics provided the basis for a new articulation of questions of distributive justice, but may have both narrowed and ‘nationalised’ the debate on inequality, foreclosing a more transversal understanding of inequalities on a global scale.