• Former President Donald Trump, on a Joe Rogan podcast, accused Taiwan of stealing America's chip industry and said he'd put a tariff on Taiwan's chips.
• Nvidia and every hyperscaler depend on Taiwan's chips to build AI models.
• Citi says tariffs would increase costs across the entire technology supply chain.

Former President Donald Trump reiterated his frustration with Taiwan over the weekend when he appeared on "The Joe Rogan Experience" podcast and accused Taiwan of stealing America's chip industry.

Trump criticized the U.S. CHIPS Act and said he would implement tariffs on chips from Taiwan if elected president. Such tariffs would impact the global leader in chip building, Taiwan Semiconductor Manufacturing Company, whose customers include companies such as Nvidia and Apple.

Shares of Taiwan Semiconductor closed down 4.3% on Monday.

"You know, Taiwan, they stole our chip business ... and they want protection," Trump said during his appearance on the podcast, which was published Saturday.

Every hyperscaler working on their own in-house chip, including Amazon, Google and Microsoft, depends on the Taiwanese company for manufacturing. UBS analysts estimate over 90% of the world's advanced chips are manufactured by Taiwan Semiconductor. Intel and Samsung are among the companies trying to compete, but they have faced a series of setbacks.

Given the broader geopolitical concerns surrounding Taiwan and the risk of a China invasion, pressure has been growing on U.S. companies to build an alternative to Taiwan Semiconductor in the U.S.

Intel, which has emerged as a poster child for the CHIPS Act, has faced many challenges. "We want to get leading-edge infrastructure built here in the U.S., and to be honest, from a policy standpoint, it really shouldn't matter all that much who is building it," Bernstein analyst Stacy Rasgon told CNBC.

Rasgon added that the idea that Taiwan had stolen our chips industry is "ridiculous."

Taiwan Semiconductor is on tap to receive nearly $7 billion from the U.S. Commerce Department to build its Arizona foundry as part of the CHIPS Act. On the company's earnings call two weeks ago, the company's CEO, CC Wei, said its Arizona plant was making progress, with volumes expected to ramp in 2025.

The U.S. Commerce Department funds have yet to be allocated to Taiwan Semiconductor or other major semiconductor firms. Funds are expected to be allocated by the end of this year as long as specific milestones are met.

Trump also suggested foreign companies shouldn't be able to enter the U.S. and use government money. "That chip deal is so bad," he said. "We put up billions of dollars for rich companies to come in and borrow the money and build chip companies here. They're not going to give us the good companies anyway."

Mizuho analysts recently wrote that a Trump win would be bad for Taiwan Semiconductor. Analysts at Citi are debating how much tariffs could increase the costs across the chip supply chain. They add that tariffs wouldn't be easy for governments to navigate. "[Tariffs] would require complex audits across thousand of devices, which contain a variety of chips," the Citi analysts wrote.

Markets have been keeping a close eye on the risk surrounding Taiwan, given how dependent Silicon Valley is on Taiwan Semiconductor's chips. Earlier this summer, when Trump made similar comments about Taiwan, the VanEck Semiconductor ETF (SMH) lost $675 billion in market cap in one week. Taiwan Semiconductor fell more than 10%.

U.S. companies that either have manufacturing facilities or are in the process of building them, such as Intel, Global Foundries and Texas Instruments, outperformed on the expectation that if Trump wins, he'll favor the domestic players.

However, a broader trade war could also challenge the sector. "[Under a Trump presidency], there are potentially big tariffs against China, which, as we have seen before, will elicit a China reaction as we saw with Micron," Patrick Moorhead, CEO of Moor Insights & Strategy and a top-ranked tech analyst, told CNBC.

But experts warn that if Vice President Kamala Harris wins the election, it's not an "all clear" for the semi trade. Some of the harshest export controls on China implemented under the Biden administration dramatically affected how much Nvidia and other semiconductors can sell into the country. Pre-export controls, Nvidia's business in China generated over 25% of total sales. China now accounts for less than 10% of Nvidia's revenue.