A great puzzle in today's world economy is the continued low level of long-term real interest rates in the US. Conventional macroeconomists like me look at America's current-account deficit, now running at 7 percent of GDP, and know that such vast deficits are inevitably followed by large currency depreciations. So we expect a substantial depreciation premium on US interest rates.
If the dollar falls 20 percent more against the euro sometime in the next 10 years, US long-term interest rates should be two percentage points higher than euro rates. If it falls 40 percent against the yen sometime in the next 10 years, US long-term interest rates should be four percentage points higher than Japanese rates. If it falls 60 percent against China's currency, the yuan, sometime in the next 10 years, US long-term interest rates should be six percentage points higher than Chinese rates. But we are not seeing signs of anything like this.
http://www.taipeitimes.com/News/edit/archives/2005/04/25/2003251938