Look here:
http://levin.senate.gov/newsroom/release.cfm?id=218710"The full list of companies involved is available in the GAO report. The list includes some of the biggest names in federal contracting and American business. For example:
Fluor Corporation: $932 million in federal contracts; 27 tax haven subsidiaries, including seven in Bermuda, five in Barbados, and three in Mauritius.
Exxon-Mobil: $707 million in federal contracts, 11 tax haven subsidiaries in the Bahamas.
Halliburton: $534 million in federal contracts, 17 subsidiaries in tax haven countries, including 13 in the Cayman Islands which does not impose a corporate tax.
WorldCom: $504 million in federal contracts; 10 tax haven subsidiaries, including four in Panama, three in Bermuda, and one in the Cayman Islands.
Tyco International: $206 million in federal contracts; 115 subsidiaries in tax haven countries, including eight in the Bahamas, 17 in Barbados, 55 in Bermuda, and five in the Cayman Islands.
According to FY2005 budget documents, as recently as 1943, U.S. corporations provided nearly 40 percent of total U.S. tax revenues, but now pay about seven percent. One tax expert has estimated that, on the average, large U.S. corporations today are paying an effective tax rate of 15 percent, less than half the 35 percent corporate rate in the tax code. Recently released data also shows that, in 2001, about half of all foreign profits of U.S. corporations were in tax havens."
The report itself:
http://levin.senate.gov/newsroom/supporting/2004/030404taxhavenGAOreport.pdf