Apple (AAPL), Microsoft (MSFT), Google (GOOG) and Cisco Systems (CSCO) hold a combined $124B in U.S. Treasurys and a further $39B in other government debt, the U.K.'s Bureau of Investigative Journalism calculates.
The tech giants appear to hold much U.S. debt offshore, which enables them to earn tax-free interest. Repatriating the assets would saddle them with a huge tax bill.
Unsurprisingly, Senator Carl Levin is not happy. "If a U.S. multinational puts its offshore cash into a U.S. bank and uses the money to buy U.S. Treasurys, stocks and bonds, those funds ought to be treated as having been repatriated and subject to US tax."