According to the SAP Certified Application Associate - SAP S/4HANA Finance for Group Reporting Associates (SAP S/4HANA 2021) certification exam1, the ownership chains that are supported in the equity pickup solution are:
Vertical: A vertical ownership chain is a direct or indirect ownership relationship between two units in the same consolidation group. For example, if unit A owns 80% of unit B, and unit B owns 60% of unit C, then there is a vertical ownership chain from A to C.
Horizontal: A horizontal ownership chain is an ownership relationship between two units that are not in the same consolidation group, but have a common parent unit. For example, if unit A owns 80% of unit B and 70% of unit C, then there is a horizontal ownership chain between B and C.

You cannot release data if company codes are not mapped to consolidation units or if the period is closed in group reporting. Both of these conditions prevent the release of data for consolidation.

Data slices in SAP Intercompany Matching and Reconciliation matching rules are made up of Company code and Partner unit. These two factors help to identify the corresponding transactions for matching and reconciliation purposes (SAP Help Portal: Define Matching Rules).

To run a management consolidation report, you must select a consolidation group. The consolidation group represents a set of entities whose financial data will be aggregated and reported in the management consolidation report.

The field "Percentage complementary" is used to calculate the amount by multiplying by 1 minus the ownership percentage in the rule-based consolidation of investments method.