The amount of cash held overseas by U.S. firms has risen to $2.5 trillion, according to new research by independent advisory firm Capital Economics, which suggests it's very unlikely to be ever repatriated.
"This vast pile of foreign cash could provide a substantial boost to GDP (gross domestic product) if it was ever brought home. But the chances of this happening under the current tax system are very low," Andrew Hunter, a U.S. economist at the firm, said in a new note on Monday.
Two years ago, the company estimated that the stock of earnings held abroad by U.S. corporations had increased six-fold over the previous decade, to a total of $2.1 trillion. It now states that it had risen to $2.5 trillion by the end of last year.
This news research comes on the back of a new ruling by European Union authorities, which ruled that Ireland must claw back billions in unpaid taxes from U.S. tech giant Apple. The decision has caused shockwaves in the business world with questions being raised over the future of multinationals in Europe and international taxation rules.
Apple's Chief Executive Tim Cook said earlier this month that the company expects to repatriate billions of dollars of global profits to the United States next year, without specifying exactly how much would be returned. Apple had been found to be holding over $181 billion in accumulated profits offshore, according to Reuters who cited a study published last year by two left-leaning nonprofit groups.
Capital Economics estimate that Apple now has $91.5 billion of earnings permanently reinvested overseas, but said that it is not the biggest holder. General Electric and Microsoft have more than $100 billion each, it said. GE was not immediately available for comment when contacted by CNBC and Microsoft declined to comment.
"The U.S. requires firms to pay the full 35 percent corporate tax rate – the highest in the developed world – on all worldwide income, but only if those funds are repatriated. This gives firms a clear incentive to keep earnings overseas," Hunter said in the note.
"That said, the prospect of a deal being agreed to reform the corporate tax system is no longer as remote as it once was," he added, referring to the campaign promises of both presidential candidates Hillary Clinton and Donald Trump.