Bright-line, factor presence nexus has become an increasingly popular issue in state taxation in recent years. While the rules and thresholds vary from state-to-state, the Multistate Tax Commission’s (“MTC”) model rule exemplifies how factor presence nexus works.  Specifically, the MTC’s model rule provides, in part, that “substantial nexus” (i.e., a taxable presence) exists for corporate income tax purposes if an out-of-state taxpayer has total sales in the state exceeding $500,000 during any given taxable period.  Several states–including Alabama, California, Colorado, New York, Ohio, and Tennessee–have adopted factor presence nexus rules; however, to date, there have been very few cases that have considered the constitutionality of bright-line, factor presence nexus standards.