1. Introduction
A longstanding puzzle is that the United States is a net borrower from the rest of the world, yet
somehow manages to, on net, receive income on its external position. Net investment income
receipts reported in the U.S. balance of payments (BOP), the top line in Figure 1, have continued
to grow even while the net liabilities position, the bottom line, has also grown. This situation has
mystified economists for almost a quarter-century:
“Clearly, if our investments abroad are yielding a positive return,
their capital value must be positive not negative. Is this a defect of
the figures on current flows, or is it a defect of the balance-sheet
figures?…” (Milton Friedman, 1987)1
The income received on the U.S. external position plays an important role in one of the biggest
issues confronting international macroeconomists—the sustainability (or lack thereof) of the U.S.
current account deficit. Net income receipts, which equaled 33% of the goods and services
balance in 2010, provide a significant stabilizing force for the current account. Future
sustainability will depend, in part, on the persistence of these net income receipts. So an
understanding of what is generating this income will help economists assess how the U.S.
imbalance might evolve.
A single asset class is responsible for the puzzle. Net income receipts in the BOP owe
entirely to a difference between the yields (income divided by the position) on direct investment
claims and liabilities (Hung and Mascaro 2004, Bosworth et al. 2008, Bridgeman 2008, Curcuru,
Dvorak and Warnock 2008). The aggregate yield on U.S. cross-border claims averaged 140 basis
points per year higher than that paid on U.S. cross-border liabilities from 1990-2010, shown in
the first columns of Figure 2. The next columns show that the main driver of this difference was
foreign direct investment (FDI); the average yield received on U.S. FDI claims was an