President Trump just made it a lot more expensive for companies to hire foreign workers through the H-1B program. The White House announced Friday that Trump signed a proclamation requiring employers to pay a hefty $100,000 fee for new H-1B visa applications, an enormous jump from the current $215 lottery registration fee.

H-1B visas allow U.S. companies to hire foreign workers in fields that typically require technical expertise like IT, engineering, mathematics, or medicine. The program is capped at 65,000 new visas annually, plus an additional 20,000 for foreign graduates with advanced degrees from U.S. universities. The visas are awarded through a lottery system and typically last three years, though holders can extend them or apply for green cards.

The administration’s new move is designed to crack down on what it calls widespread abuse of the program, which it blames for displacing American workers. According to the White House, the share of IT workers with H-1B visas has skyrocketed from 32% in 2003 to over 65% today, while unemployment among recent computer science graduates has hit 6.1%.

Silicon Valley will undoubtedly be up in arms over the initiative. The restrictions take aim at a program that helped create some of the region’s biggest success stories.

Elon Musk, Trump’s close ally for most of this year, initially worked in the U.S. on an H-1B after arriving as a student. In fact, Musk, taking issue with a perceived critic of the H-1B program in December on his platform X, tweeted to the individual that, “The reason I’m in America along with so many critical people who built SpaceX, Tesla and hundreds of other companies that made America strong is because of H1B. Take a big step back and F*** YOURSELF in the face. I will go to war on this issue the likes of which you cannot possibly comprehend.”

Mike Krieger, the Instagram co-founder turned Chief Product Officer at AI giant Anthropic, is one of those aforementioned success stories. The Brazilian-born Stanford grad worked at the early instant messaging platform Meebo on an H-1B visa.

Earlier this year, the National Venture Capital Association argued in a letter to the National Science Foundation that, “Raising the annual cap of H-1B visas issued each year to educated and highly skilled immigrants who work in jobs that require a substantial amount of technical and specialized training is fundamental to generating more successful immigrant-founded companies.”

The NVCA noted that while “H-1B visas are not ideal for immigrants who want to immediately found companies in the U.S., they are still critically important for the success of immigrant founded companies because they provide valuable work experience and widen the pipeline of potential immigrant startup founders.” (The H-1B’s employer-employee requirement makes it practically impossible for founders to obtain directly, forcing them to spend years tied to employers before getting green cards that let them launch their own startups. When Krieger wanted to co-found Instagram in 2010, transferring his visa took months, and he has said he almost abandoned the startup before it launched due to those complications.)

On Friday, tech leaders on X were already warning about talent fleeing to more welcoming countries. And Amazon, Google, and Microsoft have reportedly told employees with H-1B visas to avoid foreign travel and remain in the United states for now.

In the meantime, in its proclamation on Friday, the Trump administration went full bore on its criticism of the program, pointing to specific companies that approved thousands of H-1B workers while simultaneously laying off American employees. According to the White House fact sheet, one unnamed company received approval for 5,189 H-1B workers this fiscal year while cutting roughly 16,000 U.S. jobs.

The proclamation — which says it is partly rooted in an effort to “protect our national security” — includes wiggle room; case-by-case exemptions are possible if deemed in the national interest.

It also directs the Labor Secretary to revise wage requirements to prevent undercutting American salaries.

This post has been updated to include reports on how Amazon, Google, and Microsoft are responding.