Relocating only the final assembly of an imported industrial machine into the United States is not, by itself, a tariff loophole: U.S. Customs applies the substantial-transformation test, and if the last substantial transformation still occurs abroad the goods keep their foreign country of origin and the same duty line follows [S3].
For industrial equipment buyers the practical exposure is concrete. AGC's Tariff Resource Center lists 50% Section 232 duties on items made entirely or mostly from steel, aluminum, or copper, 25% on derivatives of those metals, 15% on industrial and electrical grid equipment that contains them, 10% on products made abroad but entirely with American-origin steel, aluminum, and copper, 15% on agricultural and industrial equipment such as bulldozers and forklifts, and 15% on HVAC systems and components [S2]. Stacked on top of any 10-12.5% IEEPA reciprocal layer, the final landed cost is rarely the headline rate.
What "Substantial Transformation" Actually Means for COO
Country of origin is defined as the country where a product undergoes its last substantial transformation, meaning where the most significant manufacturing or assembly activity takes place, and that determination drives which HTSUS line and which duty applies [S1].
For a heavy machine this is rarely a trivial question. A backpack made from Chinese fabric and finished in Mexico can be reclassified to a USMCA-preferential line and enter the U.S. at a much lower duty [S1]. A computer whose motherboard is built in Taiwan but is finally assembled, tested, and packaged in the U.S. can be reclassified as a U.S.-origin good [S1]. A piece of jewelry cast in India and merely polished in the U.S. can also pick up U.S. origin [S1]. The test is operationally identical across product classes: which country's operations give the article a new name, character, or use distinct from what it had on entry.
Just shifting a screwdriver station across the border is not enough. Harris Sliwoski's compliance guide is explicit that "relocating assembly alone does not change a product's country of origin" if the imported components still constitute a complete or near-complete article that only needs trivial finishing in the U.S. [S3]. The same article notes that targeted Trump-era measures have already metastasized from a roughly $380 billion import base to a shifting maze affecting more than a trillion dollars of trade, so the stakes of getting the COO call wrong are real [S3].
Where Section 232 Already Locks Down the Workaround
The October 17, 2025 Section 232 proclamation on medium- and heavy-duty vehicles expressly closes the knock-down loophole, covering vehicles imported in "knock-down" form for final assembly in the U.S. "to prevent circumvention" [S4].
The mechanics of that proclamation are instructive for any industrial-equipment buyer weighing a similar move. It covers MHDVs in Classes 4 through 8 (gross vehicle weight rating of 14,001 lb, roughly 6,351 kg, and above), MHDV parts including engines, transmissions, batteries, castings, forgings, axles, and chassis frames, and buses under HTSUS 8702 [S4]. The duties are 25% ad valorem on MHDVs and specified MHDV parts, and 10% on buses [S4]. Knock-down kits, as determined by CBP, continue to be subject to the additional duty regardless of USMCA qualification, and do not qualify for import adjustment offsets [S4].
USMCA-origin vehicles do get partial relief: the 25% applies only to the non-U.S. content, provided the importer files documentation verifying U.S. value-added with Commerce, and USMCA-origin MHDV parts will not be formally tariffed until Commerce establishes a process for that non-U.S.-content calculation [S4]. For an industrial-equipment OEM, the same architecture, knock-down kits still dutiable, USMCA components partially exempt subject to paperwork, is the model to plan against if similar Section 232 actions are extended to bulldozers, forklifts, or generator sets.
Side-by-Side: How Three Industrial Sourcing Strategies Compare
Below is a working comparison of three common paths an industrial-equipment buyer can take, lined up against the four decision points that actually drive the duty. [S2]
Strategy A: import a fully built foreign machine (no U.S. assembly). COO is the factory country; HTSUS line is the finished-goods line; duty stacks Section 232 metal content (up to 50%), 15% on industrial/grid equipment containing steel/aluminum/copper, 15% on agricultural and industrial equipment such as bulldozers and forklifts, and 10-12.5% IEEPA reciprocal on top of the 10% universal base [S2]. This is the simplest path administratively but the most expensive line on the customs broker's invoice.
Strategy B: import components and perform meaningful final assembly in the U.S. COO shifts to U.S. if substantial transformation occurs in the U.S.; HTSUS line is the finished-goods line; duty drops to the U.S.-origin rate, which is zero for most HTSUS lines, but watch for residual Section 232 metal-content duties on imported subassemblies. This is the path that worked for the Taiwan-motherboard, U.S.-final-assembly computer example and the India-cast, U.S.-polished jewelry example [S1]. It requires real work, not just packaging.
Strategy C: import a knock-down kit and reassemble in the U.S. COO may shift to U.S. if the kit is "substantially complete," but for vehicles CBP has explicit authority to treat it as the finished article; HTSUS line can be the finished-goods line; duty under the MHDV proclamation is the full 25% with no USMCA offset, and similar treatment is a known risk in adjacent Section 232 actions [S4]. This is the most fragile strategy and the one regulators are actively targeting.
Which Buyers Should Care and Which Can Ignore It
Procurement and trade-compliance leads at OEMs importing finished industrial machines, forklifts, bulldozers, agricultural and industrial equipment, HVAC systems, or anything with substantial steel/aluminum/copper content should treat the COO question as a tier-one line item, not a customs formality, because the stacked duty math (15% on the equipment + 25-50% on the metal content + 10-12.5% IEEPA) is the difference between a workable margin and a project cancellation [S2].
Operations teams sourcing common construction machinery should expect longer lead times as dealers reorder and as some brands rebalance production between overseas and U.S. plants, a pattern already visible in the heavy-equipment market where dealers report back-orders of months for new machines [S5]. Buyers considering a move to renting rather than buying should factor in that rental rates move with the same tariff-driven input costs, so the rent-versus-buy gap narrows on big-ticket iron [S5].
Buyers of fully U.S.-built machines using entirely American steel, aluminum, and copper can rely on the explicit 10% rate on those products under AGC's summary, which is a real and verifiable carve-out worth confirming with mill certificates at the point of purchase [S2]. Buyers in construction machinery and equipment categories not yet named in a Section 232 proclamation, for example most non-vehicular plant equipment, can ignore the knock-down loophole analysis for now but should still pressure-test the COO claim with their broker, because the default rule from Harris Sliwoski is that relocating assembly alone does not change origin [S3].
Failure Modes Buyers Actually Hit
The dominant failure mode is a false assumption: "We opened a 5,000 sq ft building in Texas, so our Chinese skid is now American." If the imported skid is 90% complete and U.S. operations only add a wiring harness, U.S. Customs will treat the article as Chinese-origin and apply the full China stack, which under the AGC summary combines a 30% IEEPA layer on top of universal tariffs and any product-specific Section 232 line [S2][S3]. The same lesson shows up in the MHDV proclamation where knock-down kits, even when assembled into a complete truck in the U.S., stay dutiable at 25% with no USMCA offset [S4].
The second failure mode is paperwork. USMCA relief on MHDVs is contingent on filing U.S. value-added documentation with Commerce, and USMCA parts relief is contingent on Commerce establishing a process that has not yet been published as of the October 21, 2025 analysis [S4]. Assume relief exists, and the broker will reject the entry at the port. The third failure mode is tariff engineering that breaks HTSUS rules: reclassifying a product under a different heading to dodge a rate can backfire if CBP applies the "principal use" or "substantial transformation" tests on the importer side and assesses anti-circumvention penalties.
For a working engineer, the practical checkpoint list is short: (1) confirm the COO call with a binding CBP ruling before signing the supply contract; (2) audit the bill of materials for steel, aluminum, and copper content against the 50%/25%/15% tiers in AGC's summary [S2]; (3) if planning a U.S. assembly move, document the operations that drive substantial transformation, not just the box-stuffing; (4) for any MHDV or MHDV-adjacent product, assume knock-down kits stay dutiable until proven otherwise [S4].
What's Verifiable Now and What to Track Next
On the record as of October 2026: the 50% Section 232 rate on items made entirely or mostly from steel, aluminum, or copper, the 25% derivative rate, the 15% rate on industrial and electrical grid equipment containing those metals, the 10% rate on products made abroad but entirely with American metals, the 15% rate on agricultural and industrial equipment such as bulldozers and forklifts, the 15% rate on HVAC systems and components, and the 10% universal base with 10-12.5% IEEPA reciprocal are the published numbers from AGC's Tariff Resource Center, last updated 24 September 2026 [S2].
Trackable signals for the next 90 days: any expansion of the MHDV Section 232 architecture to non-vehicular construction machinery and equipment categories, which would import the same knock-down loophole-closure language; publication by Commerce of the USMCA-content verification process for MHDV parts, currently the gating item for the partial exemption to actually take effect [S4]; and any AGC update on whether the IEEPA Supreme Court ruling already referenced in the resource center has triggered a refund or stacking change to the 30% China line and the 15-40% reciprocal band [S2].
Detailed specification references: locking assembly, and ndt equipment.
For related coverage, see Hard-Coded Credentials in Industrial Devices vs Default Passwords: Procurement Specs.