Overview

• President Donald Trump announced the levy on Truth Social, confirming a Nov. 1 start but offering no details on exemptions or whether the duty will stack on existing tariffs.
• Mexico faces the biggest hit, with roughly 82.3% of U.S. heavy‑truck imports sourced there and trade flows in the sector estimated around $20–25 billion this year.
• The move follows a Commerce Department Section 232 probe into medium and heavy truck imports, which allows sectoral tariffs on national‑security grounds.
• The timing precedes a Supreme Court hearing on Nov. 5 over broader tariff authority; analysts note the outcome is unlikely to affect these sector‑specific measures.
• Manufacturers and suppliers are assessing impacts as prior metal tariffs have lifted input costs, and questions remain over how USMCA content rules will be treated under the new duty.