financial transaction NMGBJ9

NMGBL0=http://en.wikipedia.org/wiki/Financial_transaction
NMGBJH=the parent where it is clear what item(s) being traded are considered the http://en.wikipedia.org/wiki/Payment specifically http://en.wikipedia.org/wiki/Medium_of_exchange , so then who “buyer” vs. “seller” is.
NMGCGY=typically if not always identical to the parent.