This article moves from the premise that a bilateral relationship between law and economics requires the contribution of the theory of legal argumentation. The article shows that, to be legally relevant, economic consequences have to be incorporated into interpretive arguments. In this regard, the jurisprudential preface strategy proposed by Craswell goes in the right direction, but begs the question of why the legally relevant consequences have to be assessed in terms of total welfare maximization instead of, in the EU context at least, consumer welfare maximization. After having identified five points of divergence between total and consumer welfare approaches, the article draws from legal inferentialism to propose an analytical tool – the explanatory scorekeeping model – for assessing the explanatory power of these two approaches. The model is then applied to the reasoning in United Brands Company v. Commission.