A groundbreaking economic study from Harvard University and the University of Chicago has uncovered a substantial discrepancy between the tariff rates publicly announced by the Trump administration and what importers actually paid throughout 2025. The research demonstrates that while official figures suggested trade-weighted tariffs reaching 32.8% in April, the effective rate paid by companies stood at just 14.1% by September.
The comprehensive analysis identifies multiple factors contributing to this significant gap. Critical exemptions for products in transit during tariff announcements created implementation delays, while special considerations for semiconductor imports substantially reduced rates for technology products. Additionally, preferential treatment under the US-Mexico-Canada Agreement and widespread compliance declarations from North American trading partners further diminished the effective tariff burden.
The research further reveals that tariff evasion strategies, including misdeclaration of product content, value, and country of origin, contributed to the reduced effective rates. Contrary to administration claims that foreign exporters would absorb costs, the study found that 94% of tariff expenses were passed through to American importers in 2025, significantly higher than the 80% rate observed during the 2018-2019 China tariff implementation.
Despite the lower-than-expected effective rates, the tariffs have substantially reshaped global trade patterns. China’s share of US imports plummeted from 22% in 2017 to just 8% by late 2025. The policies have particularly affected manufacturers relying on imported components, with heavy machinery, automotive, and agricultural equipment sectors experiencing the most significant cost increases.
The administration has recently shown flexibility, delaying scheduled tariff increases on furniture and reconsidering pasta tariffs amid affordability concerns. Economists caution that with only limited data available since full implementation, the long-term economic consequences remain to be fully understood.