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.

via CNBC