This research note describes the plausible magnitude of US revenue loss due to profit shifting, building on recent developments in the literature as well as new country-by-country data on US multinational companies in 2017. In the past, the most complete data sources have all shown large magnitudes of profit shifting, suggesting substantial revenue losses in non-haven countries. Blouin and Robinson (2019) have challenged this consensus, noting that many data sources may be flawed due to the inadvertent inclusion of double-counted profits or through an inadvertent misallocation of profit. Nonetheless, their proposed correction to the data generates its own puzzles, and experts at both the BEA and the JCT believe that the proposed correction will omit some types of profit shifting. Beyond that, Blouin and Robinson’s conclusions regarding how their adjustments affect the scale of profit shifting set aside many nuances in method that affect bottom-line findings about the scale of profit shifting. This research note uses recently released country-by-country tax data to estimate plausible benchmarks regarding the scale of profit shifting, finding that profit shifting is likely to be costing the US government over $100 billion a year in 2017 (at 2017 tax rates). While much can be done to refine these estimates and learn more about the scale of the problem, the problem remains unambiguously very large.