克鲁格曼国际经济学第六版，第12章：  
A   U.S. auto   dealer   imports   a   Volkswagen from   Germany and pays the auto company   with a check  for $15,000. Volkswagen   does not want to invest the money   in dollar assets, but it so happens  that the Bundesbank   is willing to give Volkswagen   German   money   in exchange for the $15,000 check. The   Bundesbank's international   reserves   rise  by   $15,000   as  a.result   of   the   deal.  Because   the    Bundesbank's dollar   reserves are part   of  total   German   assets  held   in the  United   States, the  latter rise by $15,000. This transaction   therefore  results in a positive $15,000 entry in the U.S. financial
account,  the other   side  of  the   —$15,000 entry   in the  U.S. current   account   due  to the   purchase of the car.      

Like any summary   measure, however, the balance of payments must be interpreted   with  caution. To return to our running example, the German  Bundesbank's decision to expand its U.S.   bank    deposit   holdings   by   $15,000   swells   the   measured      U.S.  balance of payments deficit   by the same amount.  Suppose the Bundesbank   instead places  its $15,000 with   Barclays Bank   in London,  which   in turn deposits the money   with Bankers Trust   in New York. Nonreserve U.S. financial   inflows rise by $15,000 in this case, and the U.S. balance of payments  deficit   does  not rise. But this  "improvement"  in the balance  of payments is of  little economic   importance: It makes  no difference   to the  United   States  whether it borrows  the Bundesbank's  money   directly   or through a London   bank.
不明白这句是为什么“Nonreserve U.S. financial   inflows rise by $15,000 in this case, and the U.S. balance of payments  deficit   does  not rise. ”请指教~~