The term market participant is used in United Statesconstitutional law to describe a U.S. State which is acting as a producer or supplier of a marketable good or service. When a state is acting in such a role, it may permissibly discriminate against non-residents. This principle was established by the United States Supreme Court in Reeves Inc. v. Stake, 447 U.S. 429 (1980), in which the Court upheld South Dakota's right to give South Dakota residents preferential treatment in the purchase of cement produced at a cement plant owned and operated by the state.
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