It's no secret that the US government wants companies to bring more of their offshore profits back home for the sake of taxes, and it's now exceptionally clear as to why. Bloomberg has sifted through financial filings and discovered that the top eight American tech firms, including Apple, Google and Microsoft, are keeping more than $420 billion overseas -- $69 billion of it added in just the past year. That's over a fifth of the $2.1 trillion held abroad by American companies, and would easily cover a lot of government expenses. A tax on Microsoft's recent profits alone ($29.6 billion) would cover NASA and the Commerce Department for a year; Apple ($23.3 billion) could take care of the Transportation Department and Social Security, and Oracle could foot the bill for the Labor Department.