I am sure that those 2 billion dollars have gone to some other banks. banks trade among themselves so when one loses the other one gains. the big whale trade caused a loss of $5 billions. it is usual for banks to see loses of this kind. most banks have a huge exposure and take risky positions with little hedging. it the nature of the job that sees them through. investment assets like forex are huge sources of profits for banks. forex trading unlike conventional loans given to the public offers more returns and that is why banks are willing to take positions in the forex market.