On Tuesday, Donald Trump announced a plan to sell $5 million “gold card” visas that offer permanent residency and work authorization in the U.S. “Wealthy people will be coming into our country by buying this card,” Trump told reporters in the Oval Office. “They’ll be wealthy and they’ll be successful.”

Trump floated the plan, which he says will begin in two weeks, as a way to reduce the federal deficit. “We’ll be able to sell maybe a million of these cards, maybe more than that. And if you add up the numbers, they’re pretty good. As an example, a million cards would be worth $5 trillion dollars.”

But how interested are the world’s wealthiest people? Forbes spoke with 18 billionaires around the globe, spanning the Americas, Europe, Asia and Africa, to gauge their interest.

Thirteen of the billionaires—nearly three-quarters of those polled—said they would not be interested in purchasing a gold card visa, while three were on the fence. Forbes found two billionaires who said they’d seriously consider buying one.

“If you’re a billionaire, you don’t need it,” says one Canadian billionaire. “In my opinion, there is no reason for rich people to go to this program,” adds a European billionaire. “Whoever has a business idea can do it now for very cheap, so why spend $5 million?” Says one Russian billionaire: “I do not understand who will pay $5 million.”

Many wealthy non-citizens already make investments in the U.S. from abroad, tapping into the American market without seeking residency or citizenship. “I don’t have to come to the United States to invest in the United States,” says the Canadian billionaire.

Many billionaires simply don’t think they need American citizenship and don’t want it.. Some aren’t interested in moving from the countries where they built their businesses and raised their families. “I wouldn’t want to be a citizen of any country other than India anytime—but more so in this century,” says Abhay Soi, who chairs India's second-largest listed hospital chain by revenue. He is one of seven Indian billionaires polled by Forbes, all of whom said they’re not interested in a gold card.

Then there are the tax implications. The U.S. is one the few nations that taxes its citizens on their income around the world, regardless of where they reside—a major drawback to obtaining citizenship, according to several billionaires polled by Forbes. Trump said on Tuesday that gold card holders “won’t have to pay any tax on income outside of the United States,” potentially giving them a huge tax break not afforded to other visa holders or even U.S. citizens, though the details of the gold card program have not yet been released, and it remains unclear whether Trump can offer such a deal without Congressional approval. Four billionaires cited American taxes as a major concern. “I’d pay $10 million,” says a Middle East-based billionaire, who, despite having no close current commercial or personal ties to the U.S., sees the visa as a compelling opportunity, “so long as it doesn’t come with the weight of worldwide taxation.”

Several others aren’t interested in a gold card, even if they wanted to move to the U.S., because they believe they could find another path to citizenship without the hefty price tag, including through marriage or extraordinary ability visas for highly skilled workers. “If the U.S. leaves this as the only way to obtain citizenship and cancels all the others, then such an initiative will have significance,” says the Russian billionaire.

Meanwhile five moguls did express interest in the card, including one based in the Middle East, two from Europe and two from Africa.

“President Trump’s initiative strikes me as a bold idea with significant promise,” says Mohammed Dewji, a Tanzanian billionaire who lives in Dubai. “If handled with care and paired with thoughtful legal frameworks, it could help create the kind of vibrant international community I enjoy in Dubai—a global hub where innovation, capital formation and cross-border collaboration thrive.”

Reporting by Elena Berezanskaya, Kerry A. Dolan, Monica Hunter-Hart, John Hyatt, Sylvan Lebrun, Chase Peterson-Withorn and Giacomo Tognini