President-elect Donald Trump’s campaign proposal to slash taxes on cash U.S. companies have stashed outside of the country could benefit the tech industry most of all.

Companies like Apple, Microsoft, and Google are among the top holders of over $1 trillion of cash held outside of the country. The build-up is largely the result of the companies’ efforts to avoid paying taxes—including the 35% U.S. corporate tax rate—on the money in any jurisdiction.

But Trump has proposed slashing the rate to repatriate the cash to 10%. A similar temporary rate cut to 5.25% under President George W. Bush in 2004 prompted companies to bring back $312 billion. To be sure, Trump has not discussed his tax plans extensively since winning the election and might not actually go through with the repatriation rate cut plan.

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A lot of money is at stake. Excluding financial companies, U.S. companies have a total of $1.3 trillion in overseas cash, Moody’s Investors Service said in a report last week. The five companies with the most overseas cash—all tech companies—are Apple aapl , Microsoft msft , Google parent Alphabet googl , Cisco Systems csco , and Oracle orcl , according to Moody’s.

Just how much economic impact the repatriated cash would have once brought back is unclear. Tech companies have found clever ways to rely on the cash without bringing it home, such as by issuing debt or funding overseas acquisitions, like Qualcomm’s qcom recent $47 billion deal to buy NXP Semiconductors nxpi , which is based in the Netherlands.

Studies of the 2004 Bush-era repatriation tax break found that almost all of the money was used to fund stock buybacks and executive compensation. Little was used to hire more or workers or acquire capital equipment. The 15 companies that brought back the most cash reduced the size of their workforce in total and decreased spending on research and development, according to a 2011 Congressional investigation.

And that one-time break dramatically increased corporate use of tax schemes that helped avoid paying U.S. taxes on income while generating even more overseas cash. So the bottom line could be even less corporate income tax for U.S. coffers.