world trade organization/SME

Hi all, I am looking for a vocabulary/ontology for modeling small business
organizations. in this case, there is the classification micro, small,
medium, large business. I know the WTO has a vocabulary and I am sure there
must be something like that at EU level as well as in the US. Any hint as
to where could I find these resources?

EU has the NACE codes, is there a structured machine-processable (beyond
the PDF) version for NACE codes?