For decades, the American intelligence community has adhered to a norm against spying for the sake of enriching private firms. More recently, the norm has figured in a prominent presidential directive as well as in various international agreements. But notwithstanding its durability and its newfound renown, the norm has largely eluded scholarly consideration. In this Essay, I aim to address that gap by showing how theories of agency capture and institutional culture can help make sense of the norm’s past and inform judgments about its future.