International PhD students to face strict limits on time in the US
Universities in the United States would have to pay as much as US$100,000 for one of their international graduates to work in the country after their education under a new federal proposal. Credit: Getty
International students in the United States would incur a US$100,000 price tag to work in US science after graduation under a proposal made public on 7 October by the administration of US President Donald Trump.
The proposed rule would require academic institutions to foot the bill for a work programme called optional practical training (OPT), which allows overseas students to work in the United States for up to three years after finishing an undergraduate or postgraduate degree.
Roughly one-third of the 1.2 million international students in the United States participated in OPT in the 2025–26 academic year, making it the largest pipeline of global talent into the US workforce.
The US Department of Homeland Security (DHS), which issued the proposed rule, stated that it is meant to “combat fraud, strengthen the integrity of the immigration system and protect US workers”. The DHS projected that if the rule was finalized, OPT enrolment would drop by as much as 44% and universities would pay between $8.4 billion and $16.5 billion annually.
An analysis1 of the rule’s effects on OPT enrolment by Michael Clemens, an economist at the Johns Hopkins School of Government & Policy in Washington DC, projects that the number of students who enrol after a bachelor’s degree would be halved. Moreover, enrolment by those with master’s degrees would be almost eliminated. Clemens also noted that OPT is especially important for international PhD graduates in science, technology, engineering and mathematics (STEM) fields, drawing roughly 70% of them in 2022.
The proposed rule is the latest in a series of attempts by the Trump administration to restrict immigration — policies that have already limited the country’s ability to recruit scientific talent. In 2025, for example, Trump announced a $100,000 levy on H1-B visas, which are reserved for researchers and other highly skilled foreign workers. As a result, applications for those visas plummeted by 90%, according to the US Citizenship and Immigration Services.
If the latest proposal and related restrictions are implemented, the combined measures “will obliterate the pipeline” of talent, says Clemens. In a separate analysis, commissioned by the US National Academies of Science, he and his colleagues found that the size of the entire US STEM workforce would drop by 6–11% over a decade if all the administration’s proposals were implemented.
A spokesperson for the DHS said that the $100,000 charge “would strengthen programme oversight while addressing concerns of fraud and abuse”, but did not respond to questions about the impact on the international STEM talent pipeline.
High cost
The OPT programme has expanded drastically over the past decade, with international students taking advantage of it to work at top technology companies such as Google and Amazon. In 2025, the number of recent graduates who were enrolled in the programme rose by 14%, even as the number of new international students dropped, notes Violet Buxton-Walsh, an immigration policy researcher at the Institute for Progress, a non-profit think tank in Washington DC. Despite restrictions on immigrants, there “are very few who have better options than staying” in the United States, she says.
Canada recruits dozens of US scholars — including several science stars
The administration’s proposal, first reported by The Wall Street Journal, would require graduates to pay a $70,000 charge for their first year of OPT. STEM graduates would pay a further $30,000 for a two-year extension.
Without the lure of OPT, the number of international students in the United States is likely to drop sharply, several scholars told Nature. As a result, Clemens projects that US colleges and universities could lose a combined $2.5 billion to $4.2 billion each year in tuition and other revenue.
Ina Ganguli, an economist of science and innovation at the University of Massachusetts Amherst, says that the impact will go beyond numbers and finances. “It will change the type of students who are going to come to the United States,” she says, because top prospects have the freedom to look elsewhere.