U.S. companies are for the first time holding more than $2 trillion overseas, according to an analysis that paints a bleak picture of whether that money will make its way home and the limited economic impact it would have even if it does.

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Corporate cash has hit $2.1 trillion, a sixfold increase over the past 12 years, Capital Economics said, citing its own database as well as that of Audit Analytics and other sources. There is no official total, but the firm also used regulatory filings that included "indefinitely reinvested foreign earnings" to glean the total sitting outside U.S. borders.

"The latest signs suggest that, as business confidence improves in light of the continued economic recovery, U.S. firms are starting to hold less cash domestically," Capital economists Paul Dales and Andrew Hunter said in a report for clients. "However, the foreign cash piles of the largest firms have almost certainly continued to grow."

That total, while daunting in its own right, is now greater than the amount held on U.S. shores, which totals just under $1.9 trillion, according to the latest Federal Reserve flow of funds tally.

Such numbers are bound to get attention in Washington, which for years has been debating so-called repatriation measures that would allow companies to bring their cash back home at drastically reduced tax rates. The new Republican-controlled Congress is expected to take up the issue quickly when it convenes in January.

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But the Capital analysis provides little optimism in that regard. Dales and Hunter pointed out that during the 2004 tax holiday "most of that cash was used to fund dividend payouts and share buybacks rather than to boost investment." A Democratic congressional report indicated that the biggest companies receiving the benefits of $360 billion in repatriated funds actually cut a net 20,000 jobs, and that the holiday cost Treasury coffers $3.3 billion.

"This is supported by the results of a 2009 study by the (National Bureau of Economic Research), which found that every $1 that was repatriated during the tax holiday resulted in an increase of almost $1 in shareholder payouts," the Capital note said. "Around $0.80 went towards share buybacks and $0.15 to dividend payments."

Very little, then, went to hiring and reinvestment.

Tech and pharmaceutical companies hold the greatest share of overseas cash, accounting for 30 percent of the total. Companies in those sectors specifically have been under fire for a rash of "inversions," or deals that see acquirers change their domiciles from the U.S. to friendlier tax countries.

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Companies that would bring the cash home would pay the difference between the local tax rate and the U.S. levy, which is the highest in the world for corporations. Theoretically, the move could provide a 12 percent boost to gross domestic product, but the reality likely will be less substantial.

The U.S. "is also one of the few countries to tax worldwide corporate income, rather than just domestic earnings. This creates a clear incentive for companies to keep their foreign earnings abroad, and this is unlikely to change," Dales and Hunter wrote. "And even if tax laws were relaxed, it seems unlikely that foreign cash holdings would provide any significant boost to the economy."

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