When purchasing a small business does the new owner have rights to the detailed financial data or would this be considered personal information?

I understand that typically the old owner will provide financial reports to the new owner during the purchasing process and that is not my concern. My concern is in the case of computer software. Should the software provider wipe out financial the data or should they get consent from the old owner to grant all data rights including accounting & payroll data? I'm especially concerned about ex-employee personal information and historical payroll information.