The enactment of the so-called Tax Cuts and Jobs Act of 2017 (TCJA) significantly changes the landscape for tax planning and compliance by U.S. multinational corporations (MNCs). The promised shift to a more territorial system actually results in a greater likelihood that more of a U.S. MNC’s foreign income is subject to current U.S. taxation. The TCJA complicates effective tax planning for such firms, forcing them to reexamine their existing global structures and financial arrangements (i.e., the “geometry” of international tax planning). We briefly review international tax planning before the TCJA as well as some key international tax provisions in the TCJA. We then provide a method to estimate the new Global Intangible Low-Taxed Income (GILTI) tax from a U.S. MNC’s financial statements when such information is not publicly disclosed and illustrate the effective tax rate (ETR) and GILTI tax effects for a small sample of public firms after the TCJA. Finally, we discuss some likely changes in international tax planning going forward.