Wayfair has, for now, answered the question (at least, in part) of whether economic activity creates substantial nexus under the Commerce Clause for purposes of sales and use taxes. However, questions remain regarding whether and to what extent business activity tax nexus standards could be impacted. While states had boldly asserted economic nexus in the business activity tax context pre-Wayfair, the response since has been somewhat muted, until recently. Three states, Pennsylvania, Texas, and Wisconsin, have recently sought to fill in the blanks with regard to business activity tax nexus, with varied and inconsistent results that may raise more questions and concerns than answers.