ISWC numbers are allocated by an external, qualified numbering agency when all songwriters credited to the musical work have been uniquely identified by their society-assigned IPI/CAE number.

Musical works featuring songwriters that are not direct members of a collection society will not be eligible for ISWC allocation.

ISWCs can help the matching of royalties, but they are not essential. All registered musical works will be assigned unique work codes that will be shared globally between societies when matching their usage.