This module introduces the concept of state tax nexus and how a business’s activities create tax filing and payment obligations. It explores the constitutional foundation of nexus and highlights key court cases that shape current standards. The module also explains how pass-through entity (PTE) taxes work and why states offer PTE elections. Through group discussions, research activities, and practical exercises, participants will develop their ability to identify when income, sales, payroll, and economic nexus may arise in future client situations.