Silicon Valley technology start-ups and businesses, many with immigrant founders and a diverse workforce, are reacting strongly against President Trump’s executive order banning travel for nationals of certain Muslim-majority countries. President Trump’s executive order, issued late last month, halted the US refugee program for 120-days, barred Syrian refugees indefinitely, and imposed a ninety-day travel suspension on individuals from seven predominantly Muslim countries, including Iran, Iraq, Libya, Somalia, Sudan, Syria, and Yemen. The ban, which was temporarily halted on Friday by a Seattle judge, has led to widespread protests and legal challenges, and many venture capitalists and start-up founders are reporting it’s already impacted key business decisions and employee operations. "I've never seen something impact the day-to-day thought process of CEOs so fast,” Neeraj Agrawal, general partner at Battery Ventures, tells the New York Times.

"Here and now, today, we have businesses that are stopping because their employees can't travel in and out of the United States," David Cowan, a partner at Silicon Valley firm Bessemer Venture Partners, says. "This will be the No.1 cause of missed business plans in 2017." Cowan, who also sits on the board of a cybersecurity company in Israel, says the company has delayed moving its headquarters to the US because its employees are "from all sorts of countries.” Other companies have also reported delaying plans to open up US locations. Amin Shokrollahi, founder and chief executive of Kandou, a semiconductor company, is reconsidering plans to open a US design center that would have employed at least twenty people. The Iranian-German dual citizen is based in Switzerland, and he and his Iranian colleagues canceled plans to attend a trade show in Silicon Valley, where he was supposed to have received an award.

The employee base of many Silicon Valley companies is especially diverse. More than half of all "unicorns"—startups valued at $1 billion or more—have at least one immigrant founder, according to a 2016 study by the National Foundation for American Policy, a non-partisan think tank based in Arlington, Virginia. "There is a panic in the startup community," Bill Stock, president of the American Immigration Lawyers Association (AILA), tells the New York Times. "Startups are very concerned because of the unpredictability of the order."

The opposition to the travel ban is so strong that nearly 130 companies, many of them in the technology field, filed an amicus brief late Sunday in the US Court of Appeals for the Ninth Circuit, which declined to reinstate the travel ban after it had been blocked. The brief was signed by large and small tech companies including Apple, Facebook, Microsoft, Google, Uber, Tesla, and Intel and says that the “instability and uncertainty” created by the executive order “will make it far more difficult and expensive for US companies to hire some of the world’s best talent—and impede them from competing in the global marketplace.” President Trump says the ban is necessary to protect Americans, objecting to the judicial ruling that blocked his ban: "The judge opens our country to potential terrorists and others that do not have our best interests at heart. Bad people are very happy!"

While many technology companies have been outspoken in their protest of the ban, other companies are keeping quiet. Fortune Magazine contacted nearly every company in the Fortune 100 for a response to the Muslim ban, and the “responses were almost uniformly no-comments or punts, with spokespeople explaining executives were still assessing the impacts of the ban.”

For many people landing a job at a tech company in Silicon Valley is a dream come true. Years of hard work, talent, and education have finally paid off and led to coveted positions at prestigious companies (with sweet perks). But not everyone making the move to the US benefits. The Guardian takes a look at H-4 spouses–that is, the spouses of H-1B visa holders–and in particular, the wives of Silicon Valley workers who “are integral to the continued success of the Valley’s multibillion-dollar computing industry – but also entirely invisible to it.” Many of these H-4 holders are the spouses of engineers from around the world who work at companies such as Apple, Google, and Facebook.

The majority of H-4 spouses are not authorized to work in the US (except those whose spouses have reached a certain step of their Green Card application). Therefore, many H-4 spouses give up careers in their home country to follow their spouses who have been offered dream jobs and salaries too good to refuse in the US. One new H-4 arrival tells The Guardian: “Before, I was very career-focused…my career was my identity. Coming here has forced me to ask questions: who am I? What am I good at? What are my hobbies?”

This issue is of particular importance to Indian nationals in the US, who make up 80% of the 125,000 H-4 dependent visas. Sandhya Ravindran, a thirty-eight-year-old Indian woman who has lived in the Bay Area since 2007, says “99%” of her social network comprises other Indian H-4 wives. “Honestly? If I had known what life on an H4 would be like, I would not have come,” she says in The Guardian.

While last year the US government extended employment eligibility to certain H-4 visa holders of spouses who are seeking permanent resident status, many are still unable to work. Heather Zachernuk, a thirty-three-year New Zealander whose husband works for Apple, hasn’t been able to work since she arrived in Silicon Valley. “I feel guilt. So much guilt – for having this lifestyle...for resenting my situation even while it’s also a luxury.” The Guardian concludes: “Set against millions of vulnerable migrants, H4 visa holders are lucky. They are safe, and they are wealthy. But their experiences highlight a community of women pushed to the edges of Silicon Valley by an immigration system focused only on meeting corporations’ needs.”