When public sector employees end up working for the private firms which they monitored, regulated, and even disciplined, a clear conflict of interest arises. However, little is known about the the scale and scope of this ‘revolving door’ problem. This column presents evidence from patent examiners employed by the US Patent and Trademark Office, and shows that examiners grant considerably more patents to the firms that ultimately hire them, and that the most likely explanation is that examiners are ‘captured’. This leniency lowers the quality of patents coming out of the agency.