With respect to money, we find two types of overlapping discourse within families (Lacan, 2002): one excludes financial calculation from the family environment; the other uses it to explain tension and disputes. In the one case, inter-parental solidarity offers a “portrayal of gratuitousness” (Dechaux, 1996). In the other, it is generally supposed that money is at the root of the difficulties encountered and feeds the perverse passions (jealousy, envy, greed, covetousness, etc.) that corrode family ties. “Family” and “Money”, thus, are two incompatible, but closely linked symbolic universes, and where they overlap, problems may arise. In the present paper, we will first bring out the discreet interplay of sibling assessments, where each stakeholder’s attitude to the economic situation of the other is critical. Next, having demonstrated that money is perceived as a threat to the caring relationship expected between siblings, we will see just how underhand a role it does play in the relationship. We will conclude with a study of the rules governing inter-sibling exchanges, underlining the significance of the principle of equality.