Less than 15% of Taiwan Semiconductor Manufacturing Company’s most advanced production processes are likely to be based in the United States by 2029, despite Washington’s push to relocate a larger share of the supply chain, according to a leading Taiwanese economist cited by Focus Taiwan.

Lien Hsien-ming, president of the Chung-Hua Institution for Economic Research, said that the scale and timing of TSMC’s US investments made it improbable that advanced capacity in America would approach the levels suggested by US officials before the end of President Donald Trump’s second term.

TSMC is in the midst of a $65bn investment to build three fabrication plants in Arizona, with the first entering commercial production in late 2024. The company has also pledged a further $100bn to add three more fabs, two chip assembly facilities and a research and development centre in the US. Equipment installation is under way at the second Arizona plant, which is due to begin mass production in 2027, while construction of a third facility has only recently started. Plans for a fourth fab remain at the permitting stage.

Given those timelines, Lien argued that it would be difficult for TSMC to bring the third Arizona fab into mass production by 2029, making a much larger shift of high-end manufacturing unlikely. When set against the company’s global output of advanced chips, he estimated that less than 15% would be produced in the US by the end of Trump’s presidency.

The assessment comes after US commerce secretary Howard Lutnick said Washington aimed to draw 40% of Taiwan’s supply chain to the US within the same period. Lien said such statements should be treated with caution, noting that the US is also encouraging other chipmakers, including Intel, Micron and Samsung, to expand advanced manufacturing on American soil, which could ease pressure on TSMC if those projects proceed smoothly.

The comments coincided with a bilateral agreement under which the US and Taiwan agreed to reduce tariffs on Taiwanese goods, alongside pledges of substantial investment in the US by Taiwanese semiconductor, electronics manufacturing, artificial intelligence and energy companies. Lien said public concern should be tempered, arguing that some figures cited by US officials combine direct investment with credit guarantees and risk overstating the immediate scale of capital commitments.