The inexplicably high relative value of the US dollar, in the context of a badly-managed domestic economy that is now in recession - prompts the question as to why the demand for this currency worldwide is so large. Who is actually purchasing the US Dollar and why?
Are foreigners denied other currency options under the weight of US dollar hegemony? Perhaps many of these foreigners are not 'foreign' at all but merely the international subsidiary branches of US corporations. A Hong Kong based economist Enzio von Pfeil makes the point that many politicians and trade theorists still apply "the thinking and measurement of trade balances that was developed 500 years ago in Italy." He says that this is innapropriate in a world now vastly changed and where giant Western multinational corporate conglomerates dominate cross-border international exchange.
A huge portion of international trade could be more accurately described as NON-MARKET/NON-TRADE. Intra-corporate 'trade' between branches of the same (mostly US) transnational corporations. “In North America trade associated with U.S. parent multinationals or their foreign affiliates accounted for 54 percent of U.S. exports of goods and 36 percent of imports. Forty percent of trade between the US and Canada in 1998 was intra-corporate. “Forty percent of the US-Europe trade is between parent firms and their affiliates, and in respect of Japan and Europe, it is 55 per cent; with regard to US-Japan trade, it is 80 %.”
Enzio von Pfeil logically asks: “What is meant by "foreign ownership?...Are we talking about "pure" foreigners, or also about U.S. citizens as well as MNCs with overseas financial vehicles? He points to problems with the official Treasury records that detail the owners of US 'foreign' debt - "there appear to be no data available on how much U.S. Treasury debt is held by U.S. MNCs . What, he says, do U.S. MNCs do with at least a portion of all of that money they are making in their fabulously successful overseas operations? Optically, there is an extremely good "fit" Between the overseas investments of U.S. MNCs and "foreign" ownership of America's federal debt. This suggests that plenty of U.S. government debt is held legally by American MNCs in legitimate foreign tax havens.” 
International trade (and global intra-corporate transactions) is dominated by the use of a single currency - US dollars.
"...At present, approximately two thirds of world trade is conducted in dollars and two thirds of central banks' currency reserves are held in the American currency which remains the sole currency used by international institutions The US provides the world - but mostly itself- with these dollars by buying goods (such as oil and other commodities), and services produced by US corporations in foreign countries. Since the US does not have a corresponding need for foreign currency, it sells far fewer goods and services in return...." 
Clearly, the privileged position of the US, in terms of its relative lack of need to earn foreign currencies, is a large contributer to an ongoing over-valuation of its currency. But the huge global shadow financial system must surely have an even greater impact.
When we look at trade deficits, rather than financial deficits, the UK and US do not fare well and these nationas are also the homes of the largest transnational corporations. Clearly the governments of these two countries have actively encouraged this paradigm of trade imbalance in the first instance. They have heavily subisided their corporations on an ongoing basis, given generous grants for them to extend their operations in other nations and their artificially high exchange rates have allowed these large MNCs to accumulate foreign productive assets relatively cheaply in other countries. Essentially it is corporate imperialism by another name.
Finally, there's the third world debt crisis. One created by the deliberately lax lending policies of large US (and London) banks . Euromarket 'cowboy' salesmen from Citibank and others pushed unaffordable loans onto the leaders of 'developing' nations and the consequent debt repayments have acted as a heavy tax on every household within their borders. A tax that had to be paid (again) in overvalued US dollars . This debt, as such, has been used as an instrument of exploitation and control and its repayment continues to perpetuate and worsen global currency and trade imbalances.
 Trade myth five : foreigners finance America by Enzio von Pfeil, Hong Kong.
Also see: http://k.daum.net/qna/view.html?qid=3gnR7
 It's NOT international trade. Don't be fooled. Brenda Rosser. Thursday, July 24, 2008
 'Petrodollar or Petroeuro? A new source of global conflict.' By Cóilín Nunan. Accessed on 8th August 2008. http://www.feasta.org/documents/review2/nunan.htm
 Now that these same corporations are caught in a recession with high levels of debt are we now seeing a taxpayer-funded bailout of these same multinational corporations?
 And those London banks also involved in Euromarket lending.
 Witness Paul Volker’s raising of US interest rates to usury levels in October 1979 to maintain US dollar hegemony when the currency came under attack the year before. The most alarming result was that much of the third world debt ‘sold’ by large US banks became permanently unpayable.