Disclosure laws require individuals and organizations that spend money on political speech to make public their identities. The Supreme Court and many others laud disclosure for shining light on money in politics and combating quid pro quo corruption. But that support may be misplaced. While disclosure provides information to law enforcement and the general public, it also provides information to corrupt actors. Disclosure records can tell politicians which private actors support compliant candidates, and the records can help private actors determine which politicians reward their benefactors. Disclosure can thus bring conspirators together and reduce the uncertainty that inheres in illegal transactions. That means disclosure has crosscutting effects. It can deter corruption by increasing the likelihood of exposure, but it can also raise the benefit of corruption by increasing the certainty that parties to corrupt deals will keep their promises. When the second effect trumps, disclosure increases corruption. This analysis has implications for scholarship and law. It suggests that policymakers and judges should be less optimistic about disclosure and open to alternative corruption-fighting measures.