Financial services data architectures often fail by asking the wrong question: “Which system is the system of record?” This article argues that regulated firms operate with multiple systems of authority, while truth exists outside systems altogether. What data platforms actually manage is institutional belief: what the firm believed at a given time, based on available evidence. By separating authority, truth, and belief, firms can build architectures that preserve history, explain disagreement, and withstand regulatory scrutiny through accountable, reconstructable decision-making.