Microsoft (MSFT), Apple (AAPL), Google (GOOG) and five other tech firms now account for more than a fifth of the $2.10 trillion in profits that U.S. companies are holding overseas, according to a Bloomberg News review of the securities filings of 304 corporations.

S&P Global Ratings found in May that the top 15 companies that disclose their cash holdings by region hold 83 percent of their cash overseas, up from 70 percent in 2011.

The need for a solution is clear. The American Society of Civil Engineers estimates the U.S. will need to invest $3.6 trillion in infrastructure by 2020, with the non-profit giving the nation’s schools, roads and transit systems poor grades.

Some tax experts, however, are skeptical of S&P’s proposal.

According to the Center on Budget and Policy Priorities, the tax holiday idea has been tried before and is a proven policy failure.

Indeed, after a 2004 tax holiday, 58 of the companies that benefitted from the move slashed nearly 600,000 jobs.