Since the early year of 1980s, foreign portfolio investors have purchased important portion of U.S. treasury bond issues. Simplify short-term & long-term effects of foreigners' portfolio investment on the U.S. balance of payments.
As foreigners purchase U.S. Treasury bonds, U.S. BOP will build up in the short run. Although in the long run, U.S. BOP may deteriorate as the U.S. must pay interests & principals to foreigners. If foreign funds are utilized productively and contributes to the competitiveness of U.S. industries, conversely, U.S. BOP might develop in the long run