In the US public sector, there are many examples where a few government workers earn large amounts from overtime. Is this government inefficiency driven by insider influence, or an efficient reflection of worker preferences? We study the Los Angeles Department of Transportation, where several traffic officers earned around $100,000 in overtime pay despite an ex ante equal system called “the wheel.” We show that trade via informal networks achieves 93.6% of the maximum possible allocative efficiency. This illustrates a general idea: endogenous trading networks can create the conditions for a version of the Coase Theorem to hold.