The country classification is based upon the country of foreign parent rather than the country of the ultimate beneficial owner (although BEA publishes limited supplemental information on the position and direct investment income by country of ultimate beneficial owner).  Any direct transactions with other members of the foreign parent group are assigned to the countries of the other members.  This classification is consistent with the US balance of payments methodology, which requires that each transaction be assigned to the foreign country with which it occurred.  For other types of FDIUS statistics, the country classification is based upon the country of the ultimate beneficial owner.  For USDIA statistics, the country classification is based upon the foreign affiliate's country of operations.

The industry classification can be by industry of affiliate, by industry of sales, by industry of the ultimate beneficial owner (for FDIUS), or by industry of US parent (for USDIA).  The most widely used classification is by industry of affiliate, which assigns each affiliate to the industry that accounts for the largest percentage of the affiliate's sales.

The definition of direct investment (and as a consequence, the scope of portfolio and other investment) implies that a person in one country has a lasting interest in, and a degree of influence over, the management of a business enterprise in another country.  The criterion used in the US as set forth in the International Investment and Trade in Services Survey Act, sets ownership or control of ten per cent or more of an enterprise's voting securities as a considered evidence of a lasting interest in or a degree of influence over management.  Any foreign investment that is not direct investment by this definition is considered portfolio investment.

Stock, the direct investment position at year end, equals the year end value of the foreign parent groups' (US parents') equity (including retained earnings) in, and net outstanding loans to their US (foreign) affiliates.  The position estimates are valued on three alternative bases; the first two, current-cost and market-value, reflect prices of the current period; the third, historical-cost, reflects prices at the time of the investment.  The current-cost position estimates revalue the portion of the position that represents claims on plant, equipment, and other tangible assets from historical-cost to current prices.  The market-value position estimates revalue the equity component of the position to its current stock-market value.  Estimates of the position at current cost and market value were made available for the first time in the May and June 1991 issues of the Survey of Current Business. The historical-cost position estimates come directly from the book-value data reported in BEA's direct investment surveys.  Detailed estimates of the position by country and by industry are only available on the historical-cost basis.

Capital flows consist of equity and intercompany debt flows between US (foreign) affiliates and their foreign parent groups (US parents) and the foreign (US) parents' share in the reinvested earnings of their US (foreign) affiliates.  They represent the financing supplied to a US (foreign) affiliate by its foreign parent group (US parent).  For FDIUS, capital flows can take place between the US affiliate and the foreign parent, or other members of the parent group.  For USDIA, capital flows take place between the US parent, which represents the fully-consolidated US parent group, and its foreign affiliates.