We are selling a product to energy trading firms, and we need to know
the size of our market opportunity.  We judge the size of a
prospective customer by their "net asset value", also known sometimes
as their "assets under management".  We need two pieces of information
from some reasonably authoritative source:

- The total number of energy trading firms.  

- Their total net asset value.

World-wide figures are fine, or North American figures are fine, but
we need the same scope for both numbers, and the source needs to
specify the scope.