Such unrecorded claims are sometimes called “dark matter”. The term is borrowed from physics; dark matter cannot be seen, but its presence can be inferred from its effects on visible matter. These researchers suggest that unobserved assets, particularly intellectual property, are so large that the true claims position substantially exceeds the $ trillion in U.S. liabilities to foreigners.
A careful look at the data, however, reveals that while unrecorded intellectual property may make a modest contribution to U.S. claims, there is no evidence of large-scale mismeasurement on the order of magnitude claimed by proponents of the “dark matter” theory.