We thank Anthony Rufolo, John Yinger, Edwin Mills, and an anonymous referee for helpful comments. *The requirement is described in some detail in White v. Mass. Council of Construction Employees, Inc., 103 SCt. 1042 (1983). The order covered not only city raised funds, but all funds which the city had the authority to administer. It forced private contractors who received city contracts to hire Boston residents for 50% of their work crews. 3 The Supreme Judicial Court of Massachusetts had found the executive order to violate the Commerce Clause (384 Mass. 446,425 N.E. 2d 346 (1981). The U.S. Supreme Court then held that the Boston executive order did not violate the Commerce Clause. The Court based its decision on the distinction between the state acting as a market participant and as a regulator. Where the line between participant and regulator ought to be drawn, and whether such a distinction is the relevant one, remain interesting legal issues. 41n addition to Boston a number of other cities have residency requirements. See Hirsch and Rufolo [6] for econometric evidence that wages are significantly affected by residency requirements, implying the requirements are, on average, binding. Moreover, this use is growing. Approximately 27 states also have statutes which require preferential treatment of in-state labor and materials in state-funded projects.