Last week the Department of Homeland Security announced that it would delay—and very likely withdraw—the International Entrepreneur Rule, a set of immigration regulations proposed by the Obama administration.

The rule would have allowed qualified foreign nationals to enter the United States temporarily to build their business operations here.

The rule was supposed to take effect in January and would have permitted foreign nationals to apply to enter the United States for a maximum of five years to assist a start-up business with the potential for accelerated growth or to create American jobs. To receive the entry permit, a foreign national would have to demonstrate that the start-up had received at least $250,000 in capital from certain qualified U.S. investors with established records of recent successful investments, had received federal or state grants of at least $100,000, or provide other compelling evidence of the start-up’s potential for rapid growth and job creation.

The technology sector had strongly supported the rule, as did many business and investment groups such as the National Venture Capital Association. The Trump administration’s announcement, however, provided no explanation for axing the rule.

So what are the next generation of Elon Musks, Jerry Yangs, and Liz Claibornes to do? A number of work visas could be available to them, including visas for intra-company transferees (L class), specialty occupation workers (H-1B visas), investors from treaty nations (E visas), and foreign nationals wishing to move to the U.S. permanently and willing to invest a minimum of $500,000 in certain U.S. businesses (EB-5). But each of these visas has its own requirements and limitations. The International Entrepreneur Rule was designed to fill a gap in the patchwork of visas and would have been the only available option for those entrepreneurs with no other suitable visa alternatives.

For those entrepreneurs, it’s unclear what the future holds, but it won’t involve growing their businesses in the U.S.