Economic nexus creates corporate income tax by state filing obligations for corporations exceeding a state’s revenue threshold — even without physical presence. Specifically, Illinois, New Jersey, and Colorado trigger obligations at just $100,000 in annual in-state sales. A corporation selling $8,334 per month into any of these three states must file corporate income tax returns there. Consequently, digital product sellers, SaaS companies, and remote service providers have seen state corporate income tax filing obligations multiply dramatically since Wayfair. Furthermore, corporations that fail to register in economic nexus states face back-tax assessments with penalties and interest. BermudaFin has seen assessments reach $2.1M for a single mid-market corporation across five unreported nexus states. Additionally, voluntary disclosure programs in most states allow corporations to limit back-tax exposure and eliminate penalties when filing obligations are self-identified before audit.