As most SAP users are employees of the company, their master data, such as name, e-mail address, etc., is maintained multiple times: as employees in the HR system, in the user master in SU01 and as business partners of the employee type.
In the classic user concept all three entities use their own data repository. Data changes have to be maintained within all participating entities separately.

This harbours the risk of inconsistencies and also generates additional maintenance work. The business user concept is designed to avoid this.
SAP S/4HANA is introducing a new identity model for business users, which is based on the "principle of one". A business user is defined as a natural person who is represented by a business partner and a link to a user in the system. Business users interact with the software in the context of a business process, for example, in the role of a purchaser, a sales representative, or a production planner.
SAP S/4HANA Business User Management enables and supports the entire life cycle of business users such as organizational changes, change of employment, or retirement. A user in SAP S/4HANA has a one-to-one relationship with a corresponding business partner (natural person). This reduces redundant maintenance and prevents outdated information. Personal data and workplace address data can be obtained centrally.

User and Business User
The business user is a SU01 user, but also has a one-to-one relation to the corresponding business partner. This relationship is time independent and cannot be changed anymore.
The business user concept is used in many new applications in SAP S/4HANA. SU01 users with Classic Address (Identity Address Type 00 - User's Old Type 3 Address) lead to limitations because the new business user model is a prerequisite for many business applications. As soon as Fiori apps are activated and used, business users are mandatory (for example Teams, CreditAnalyst in Credit Management or Situations).
The business partner contains the personal information, for example private address, workplace address, bank details, vendor and customer related data. The business partner and SU01 user share personal details and workplace address related data. The advantage of the new business user model is that the entire lifecycle of that person works without redundant maintenance of user address data. Business users can still be managed using transaction SU01, Central User Administration or identity management systems.
Note
In the SAP Business Suite, you can use transaction BP (Business Partner Maintenance) to assign users to business partners. In SAP S/4HANA this is not possible anymore to avoid an inconsistent data model for business users. Existing business partners cannot be converted to business users, because of Data Protection and Privacy (DPP). Already existing business partners could have been part of a distribution scenario.
With the new business user model in SAP S/4HANA we have a clear maintenance ownership. It can be owned by Human Capital Management (HCM), Business Partner (BP) or User Management. The ownership of HCM is only relevant when HCM integration is active.
Using the example of SU01 the following data categories exist:
- Person
The personal data for the business user is derived from the corresponding business partner. In case HCM integration is active this data is mapped from the corresponding employee of the HCM system (SAP SuccessFactors or SAP HCM).
- Work Center
The work center data for the business user is derived from the workplace address of the corresponding business partner. In case HCM integration is active, the function and department fields are mapped by default from the corresponding employee of the HCM system.
- Communication
The communication data for the business user is derived from the workplace address of the corresponding business partner.
- Company
During the conversion of a SU01 user from SAP Business Suite (classic user) to a business user in SAP S/4HANA the company address is copied to the business partner workplace address.
The business partner data are centrally hosted. The assignment between business partner and user is always 1:1. You can assign one user to each business partner.
Note
Users can still be maintained in SU01. The business user merely provides an additional option for user master data maintenance.
However, business users can only be created for employees and, if applicable, business partners. Technical users, for example for interfaces (RFC) or batch processing as well as other, non-personal users must be managed in SU01 as before.