# MA parent lineage events, acquisitions, mergers, novations, renames and divestitures with a citation and what the CMS file measured

`medicare_semantic.fact_parent_lineage_event_v1` · Medicare Advantage, Part D, Medicaid · status live · 58 rows

The event half of ADR M-6. Each row carries event_name, event_type (acquisition, merger, novation, divestiture, rebrand), announced_date, effective_date (the close), cms_recognition_month (the first month the CMS file carries the successor on the moved contracts, measured), predecessor and successor parents, the contracts the seed cites and the contracts the CMS file shows moving within six months of the close (with members moved), enrollment_at_event and transaction_value_usd where cited, cascade_strategy, and one citation. Entity-level events drive the acquisition segments of dim_parent_alias_v1; contract-level divestitures (a PDP book sold while the parent continues) are recorded here only.

**Grain.** One row per event_id. 58 events (measured 2026-09-30), 20 from the M-6 Phase 1 seed (lineage_event.yaml) and 38 from ma_parent_lineage_v1.yaml.

| column | type | meaning |
|---|---|---|
| event_id | string |  |
| event_name | string |  |
| event_type | string |  |
| announced_date | date |  |
| effective_date | date |  |
| cms_recognition_month | date |  |
| predecessor_parents | string |  |
| successor_parents | string |  |
| affected_contracts_cited | string |  |
| affected_contracts_measured | string |  |
| contracts_moved_measured | bigint |  |
| members_moved_measured | bigint |  |
| enrollment_at_event_cited | bigint |  |
| transaction_value_usd | bigint |  |
| cascade_strategy | string |  |
| citation_source_type | string |  |
| citation_url | string |  |
| citation_accessed_at | date |  |
| citation_snippet | string |  |
| registry | string |  |
| built_at | string |  |

Query it: `query_substrate` with `SELECT ... FROM medicare_semantic.fact_parent_lineage_event_v1 WHERE ... LIMIT 100`; read `describe_data_source("medicare_semantic.fact_parent_lineage_event_v1")` first.