There is a functionality allowing copying vendors from one legal entity to another (Copy > Add vendor to another legal entity) but in those cases number sequence for vendor account will be different. If shared number sequence is used, there is another option which will appear when creating already existing vendor: “Existing vendor. Copy vendor?”. This allows the system to copy the same account number for the same vendors in different entities. However, the functionality doesn't work if there is some country specific fields (such as 1099 tab in US countries) and in those cases copying cannot be completed due to errors stating that this fields do not existing in 1099 table.

As advised, this is currently by design.