Use EC01 to copy an existing company code. This will ensure that you will not missed out any customizing settings.
OKKP - Assign company code to the
controlling area
OBY6 - Define company code golbal
parameters
OB62 - Assign company code to chart
of accounts
Then check the following if needed, there may be other areas depending on your needs:
OBA4 - FI Tolerance Group for Users
FBZP - Maintain Payment program
OBYA - Inter Company code clearing
if being used
Return to :-
SAP Hints and Tips on Configuration
and ABAP/4 Programming