The CEO of General Motors has flagged that a border-adjustable tax could be “harmful” if not carefully integrated into a broader tax reform. GM’s supply chain within NAFTA involved exporting car parts (which would be tax deductible) to Mexico and importing autos worth around $2 billion per year. Those would not be tax-deductible. Outside NAFTA, Panjiva’s teardown of GM’s U.S. sourcing shows its largest exposure is to China (38% of the total), led by wheel supplier Citic Dicastal. Second place is batteries sourced from South Korea, accounting for 9% of all imports.