diff --git a/backend-compliance/compliance/data/use_case_registry.py b/backend-compliance/compliance/data/use_case_registry.py
index 887ba673..ca75c706 100644
--- a/backend-compliance/compliance/data/use_case_registry.py
+++ b/backend-compliance/compliance/data/use_case_registry.py
@@ -28,7 +28,9 @@ VERIFICATION_METHODS: tuple[str, ...] = (
     "manual",       # menschliche Attestierung
 )
 
-USE_CASE_GROUPS: tuple[str, ...] = ("document", "security", "cross_cutting")
+USE_CASE_GROUPS: tuple[str, ...] = (
+    "document", "security", "cross_cutting", "product",
+)
 
 
 @dataclass(frozen=True)
@@ -136,9 +138,188 @@ _USE_CASES: tuple[UseCase, ...] = (
                                   "hybrid"),
             categories=("security", "governance", "operations"),
             keyword_tokens=("tisax", "vda", "prototypenschutz")),
+    UseCase("kritis", "KRITIS / NIS2-Umsetzung", "security",
+            regulations=("KRITIS-Dachgesetz", "BSI-KritisV", "BSIG"),
+            verification_methods=("it_process", "network", "document")),
+    UseCase("dora", "DORA (Digital Operational Resilience)",
+            "cross_cutting", regulations=("DORA",),
+            verification_methods=("it_process", "document", "network")),
+    # ── Produkt-/Sektor-Use-Cases (je Quell-Regulierung) ────────────
+    UseCase("ai_act", "KI-Verordnung (AI Act)", "product",
+            regulations=("KI-Verordnung", "AI Act", "NIST AI RMF"),
+            verification_methods=("document", "it_process", "source_code")),
+    UseCase("mica", "Markets in Crypto-Assets (MiCA)", "product",
+            regulations=("MiCA",),
+            verification_methods=("document", "it_process")),
+    UseCase("mdr", "Medizinprodukte (MDR)", "product",
+            regulations=("MDR",),
+            verification_methods=("document", "source_code", "it_process")),
+    UseCase("maschinen", "Maschinenverordnung", "product",
+            regulations=("Maschinenverordnung",),
+            verification_methods=("document", "source_code", "it_process")),
+    UseCase("batterie", "Batterieverordnung", "product",
+            regulations=("Batterieverordnung", "Batteriegesetz"),
+            verification_methods=("document", "it_process")),
+    UseCase("ehds", "European Health Data Space", "product",
+            regulations=("EHDS",),
+            verification_methods=("document", "it_process", "source_code")),
+    UseCase("produktsicherheit", "Produktsicherheit (GPSR)", "product",
+            regulations=("Produktsicherheitsverordnung", "EU Blue Guide"),
+            verification_methods=("document", "it_process")),
+    UseCase("dsa", "Digital Services Act", "product",
+            regulations=("Digital Services Act",),
+            verification_methods=("document", "it_process")),
+    UseCase("dma", "Digital Markets Act", "product",
+            regulations=("Digital Markets Act",),
+            verification_methods=("document", "it_process")),
+    UseCase("data_governance", "Data Act / Data Governance Act", "product",
+            regulations=("Data Act", "Data Governance Act"),
+            verification_methods=("document", "it_process")),
+    UseCase("zahlungsdienste", "Zahlungsdienste (PSD2)", "product",
+            regulations=("Zahlungsdiensterichtlinie",),
+            verification_methods=("document", "it_process", "source_code")),
+    UseCase("geldwaesche", "Geldwäsche (AML/GwG)", "product",
+            regulations=("AML-Verordnung", "GwG"),
+            verification_methods=("document", "it_process")),
+    UseCase("lieferkette", "Lieferkettensorgfalt (LkSG)", "product",
+            regulations=("LkSG",),
+            verification_methods=("document", "it_process")),
+    UseCase("whistleblowing", "Hinweisgeberschutz (HinSchG)", "product",
+            regulations=("HinSchG",),
+            verification_methods=("document", "it_process")),
+    UseCase("barrierefreiheit", "Barrierefreiheit (EAA)", "product",
+            regulations=("European Accessibility Act",),
+            verification_methods=("document", "source_code")),
+    # ── Weitere Rechts-Use-Cases (Dokument) ─────────────────────────
+    UseCase("verbraucherschutz", "Verbraucherschutz", "document",
+            regulations=("Konsumentenschutzgesetz",
+                         "Digitale-Inhalte-Richtlinie"),
+            verification_methods=("document",)),
+    UseCase("urheberrecht", "Urheberrecht", "document",
+            regulations=("UrhG", "DSM-Urheberrechtsrichtlinie"),
+            verification_methods=("document",)),
+    UseCase("wettbewerbsrecht", "Wettbewerbsrecht (UWG)", "document",
+            regulations=("UWG",), verification_methods=("document",)),
+    UseCase("gleichbehandlung", "Gleichbehandlung (AGG)", "document",
+            regulations=("AGG",),
+            verification_methods=("document", "it_process")),
+    UseCase("steuerrecht", "Steuerrecht", "document",
+            regulations=("Abgabenordnung", "BAO"),
+            verification_methods=("document", "it_process")),
+    UseCase("handelsrecht", "Handelsrecht", "document",
+            regulations=("HGB", "UGB", "ABGB"),
+            verification_methods=("document", "it_process")),
 )
 
 
+# Deterministischer Quell-Regulierung → Use-Case-Mapper.
+# control_parent_links.source_regulation (117 distinct) → ~30 Domaenen.
+# Reihenfolge = SPEZIFISCH zuerst (Substring, case-insensitive); der erste
+# Treffer gewinnt. Die Datenschutz-Catch-alls (edpb/dsk/dsgvo) ganz hinten,
+# damit spezifische Regeln (z.B. 'DSK OH Telemedien') zuerst greifen koennen.
+_REGULATION_RULES: tuple[tuple[str, str], ...] = (
+    # Security / Code (Security-Team)
+    ("owasp", "code_security"),
+    ("nist sp 800-218", "code_security"),
+    ("ssdf", "code_security"),
+    ("nist sp 800-63", "code_security"),
+    ("nistir 8259", "code_security"),
+    ("cisa", "code_security"),
+    ("nist sp 800-207", "network_security"),
+    ("zero trust", "network_security"),
+    ("nis2", "network_security"),
+    ("nis-2", "network_security"),
+    ("enisa", "network_security"),
+    ("bsi-gesetz", "network_security"),
+    ("bsig", "network_security"),
+    ("cybersecurity act", "network_security"),
+    ("kritis", "kritis"),
+    ("nist cybersecurity framework", "isms"),
+    ("nist sp 800-53", "isms"),
+    ("digital operational resilience", "dora"),
+    ("dora", "dora"),
+    # Produkt / Sektor
+    ("cyber resilience act", "cra"),
+    ("(cra)", "cra"),
+    ("nist ai risk", "ai_act"),
+    ("ki-verordnung", "ai_act"),
+    ("ki-vo", "ai_act"),
+    ("ai act", "ai_act"),
+    ("oecd ki", "ai_act"),
+    ("crypto-assets", "mica"),
+    ("mica", "mica"),
+    ("medizinprodukte", "mdr"),
+    ("(mdr)", "mdr"),
+    ("maschinenverordnung", "maschinen"),
+    ("batterie", "batterie"),
+    ("health data space", "ehds"),
+    ("produktsicherheit", "produktsicherheit"),
+    ("blue guide", "produktsicherheit"),
+    ("digital services act", "dsa"),
+    ("digital markets act", "dma"),
+    ("data act", "data_governance"),
+    ("data governance", "data_governance"),
+    ("zahlungsdienste", "zahlungsdienste"),
+    ("geldwaesche", "geldwaesche"),
+    ("aml-verordnung", "geldwaesche"),
+    ("lieferkettensorgfalt", "lieferkette"),
+    ("lksg", "lieferkette"),
+    ("hinweisgeberschutz", "whistleblowing"),
+    ("hinschg", "whistleblowing"),
+    ("accessibility act", "barrierefreiheit"),
+    # Website / Telemedien / Recht (User-Domaene)
+    ("tdddg", "cookie_banner"),
+    ("eprivacy", "cookie_banner"),
+    ("telemedien", "impressum"),
+    ("telekommunikationsgesetz", "impressum"),
+    ("tkg", "impressum"),
+    ("tmg", "impressum"),
+    ("mediengesetz", "impressum"),
+    ("gewerbeordnung", "impressum"),
+    ("e-commerce", "agb"),
+    ("digitale-inhalte", "agb"),
+    ("konsumentenschutz", "verbraucherschutz"),
+    ("urheberrecht", "urheberrecht"),
+    ("urhg", "urheberrecht"),
+    ("uwg", "wettbewerbsrecht"),
+    ("handelsgesetzbuch", "handelsrecht"),
+    ("hgb", "handelsrecht"),
+    ("ugb", "handelsrecht"),
+    ("abgb", "handelsrecht"),
+    ("bgb", "agb"),
+    ("gleichbehandlung", "gleichbehandlung"),
+    ("(agg)", "gleichbehandlung"),
+    ("abgabenordnung", "steuerrecht"),
+    ("bao", "steuerrecht"),
+    ("standardvertragsklauseln", "avv"),
+    ("(scc)", "avv"),
+    # Datenschutz-Catch-alls (zuletzt)
+    ("nist privacy framework", "dse"),
+    ("dsgvo", "dse"),
+    ("datenschutzgesetz", "dse"),
+    ("bdsg", "dse"),
+    ("edpb", "dse"),
+    ("edps", "dse"),
+    ("dsk ", "dse"),
+    ("wp29", "dse"),
+    ("bfdi", "dse"),
+    ("data privacy framework", "dse"),
+    ("datenschutz", "dse"),
+)
+
+
+def use_case_for_regulation(regulation: str | None) -> str | None:
+    """Deterministisch: Quell-Regulierung → Domaenen-Use-Case (erster
+    Substring-Treffer). None wenn keine Regel passt (→ Fallback/Review)."""
+    if not regulation:
+        return None
+    low = regulation.lower()
+    for needle, uc in _REGULATION_RULES:
+        if needle in low:
+            return uc
+    return None
+
+
 REGISTRY: dict[str, UseCase] = {uc.key: uc for uc in _USE_CASES}
 
 
diff --git a/backend-compliance/migrations/150_mc_primary_and_regulations.sql b/backend-compliance/migrations/150_mc_primary_and_regulations.sql
new file mode 100644
index 00000000..4ad0bc38
--- /dev/null
+++ b/backend-compliance/migrations/150_mc_primary_and_regulations.sql
@@ -0,0 +1,40 @@
+-- Migration 150: Primaerzweck-Flag + MC <-> Quell-Regulierung (n:m)
+-- Erweitert das Use-Case-Mapping um (a) is_primary (Primaerzweck pro MC)
+-- und (b) mc_regulations (die feine Quell-Regulierungs-Filter-Dimension,
+-- 117 Werte). Strikt add-only. [migration-approved]
+
+SET search_path TO compliance, public;
+
+DO $$
+BEGIN
+  IF EXISTS (SELECT 1 FROM information_schema.tables
+             WHERE table_schema='compliance'
+               AND table_name='mc_use_case_mappings') THEN
+    ALTER TABLE mc_use_case_mappings
+        ADD COLUMN IF NOT EXISTS is_primary BOOLEAN NOT NULL DEFAULT FALSE;
+    CREATE INDEX IF NOT EXISTS idx_mcuc_primary
+        ON mc_use_case_mappings(use_case) WHERE is_primary;
+  END IF;
+
+  IF EXISTS (SELECT 1 FROM information_schema.tables
+             WHERE table_schema='compliance'
+               AND table_name='master_controls') THEN
+    CREATE TABLE IF NOT EXISTS mc_regulations (
+        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+        master_control_uuid UUID NOT NULL
+            REFERENCES master_controls(id) ON DELETE CASCADE,
+        master_control_id VARCHAR(60) NOT NULL,
+        source_regulation VARCHAR(160) NOT NULL,
+        is_primary BOOLEAN NOT NULL DEFAULT FALSE,
+        member_count INTEGER DEFAULT 0,
+        method VARCHAR(20) NOT NULL DEFAULT 'lineage'
+            CHECK (method IN ('lineage', 'manual')),
+        created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+        UNIQUE (master_control_uuid, source_regulation)
+    );
+    CREATE INDEX IF NOT EXISTS idx_mcreg_regulation
+        ON mc_regulations(source_regulation);
+    CREATE INDEX IF NOT EXISTS idx_mcreg_mc
+        ON mc_regulations(master_control_uuid);
+  END IF;
+END $$;
diff --git a/backend-compliance/scripts/classify_mc_use_cases.py b/backend-compliance/scripts/classify_mc_use_cases.py
index 60421cdb..6b25e9aa 100644
--- a/backend-compliance/scripts/classify_mc_use_cases.py
+++ b/backend-compliance/scripts/classify_mc_use_cases.py
@@ -1,9 +1,12 @@
-"""Klassifiziert Master Controls auf Use Cases (n:m) + Verifikations-Methode.
+"""Klassifiziert Master Controls deterministisch auf Use Cases (n:m) +
+Quell-Regulierung (n:m) + Verifikations-Methode.
 
-Stufe 1 — Seed (kein LLM, gratis): aus vorhandenen Member-Signalen
-  (canonical_controls.scope_doc_type / .category / .verification_method /
-   .evidence_type) via `use_case_registry.seed_classify`.
-Stufe 2 — LLM (Phase 3): Multi-Label gegen die Registry-Taxonomie. [TODO]
+DETERMINISTISCH (kein LLM): Die Zuordnung kommt aus der Quell-Regulierung
+jedes Controls — Lineage master_controls -> master_control_members ->
+control_parent_links.source_regulation. 117 Regulierungen -> Keyword-Mapper
+(use_case_registry.use_case_for_regulation) -> ~30 Domaenen-Use-Cases.
+Primaerzweck = dominante Quell-Regulierung (meiste Member); Mehrfachzwecke =
+die weiteren. LLM-Stufe (spaeter) nur Fallback fuer MCs ohne source_regulation.
 
 Lauf im Container:
   docker exec bp-compliance-backend \
@@ -15,83 +18,131 @@ from __future__ import annotations
 import argparse
 import asyncio
 import os
+import sys
 
-import asyncpg
+# /app auf den Pfad, damit `compliance...` als Standalone-Script importierbar
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-from compliance.data import use_case_registry as reg
+import asyncpg  # noqa: E402
 
-_AGG_SQL = """
+from compliance.data import use_case_registry as reg  # noqa: E402
+
+_REG_SQL = """
 SELECT mc.id AS mc_uuid, mc.master_control_id,
-       array_agg(DISTINCT cc.scope_doc_type)      AS scopes,
-       array_agg(DISTINCT cc.category)            AS categories,
-       array_agg(DISTINCT cc.verification_method) AS vmethods,
-       array_agg(DISTINCT cc.evidence_type)       AS etypes
+       cpl.source_regulation AS reg, count(*) AS cnt
 FROM compliance.master_controls mc
-JOIN compliance.master_control_members mcm
-     ON mcm.master_control_uuid = mc.id
+JOIN compliance.master_control_members mcm ON mcm.master_control_uuid = mc.id
+JOIN compliance.control_parent_links cpl ON cpl.control_uuid = mcm.control_uuid
+WHERE cpl.source_regulation IS NOT NULL AND cpl.source_regulation <> ''
+GROUP BY mc.id, mc.master_control_id, cpl.source_regulation
+"""
+
+_VERIF_SQL = """
+SELECT mc.id AS mc_uuid,
+       array_agg(DISTINCT cc.verification_method) AS vmethods,
+       array_agg(DISTINCT cc.evidence_type) AS etypes
+FROM compliance.master_controls mc
+JOIN compliance.master_control_members mcm ON mcm.master_control_uuid = mc.id
 JOIN compliance.canonical_controls cc ON cc.id = mcm.control_uuid
-GROUP BY mc.id, mc.master_control_id
+GROUP BY mc.id
 """
 
 
 async def run_seed(conn, limit: int = 0) -> dict:
-    """Deterministischer Seed → mc_use_case_mappings + mc_verification.
-    Idempotent (ON CONFLICT DO NOTHING); ueberschreibt 'manual' nie."""
-    sql = _AGG_SQL + (f" LIMIT {limit}" if limit > 0 else "")
-    rows = await conn.fetch(sql)
-    n_mc_with_uc = n_uc_rows = n_verif = 0
-    for r in rows:
-        ucs, method = reg.seed_classify(
-            r["scopes"], r["categories"], r["vmethods"], r["etypes"],
-        )
-        for uc in ucs:
+    """Deterministischer Seed aus der Quell-Regulierung. Ersetzt die
+    bisherigen Seed-Zeilen; 'manual'-Korrekturen bleiben unangetastet."""
+    await conn.execute(
+        "DELETE FROM compliance.mc_use_case_mappings WHERE method='seed'")
+    await conn.execute(
+        "DELETE FROM compliance.mc_verification WHERE method='seed'")
+    await conn.execute(
+        "DELETE FROM compliance.mc_regulations WHERE method='lineage'")
+
+    by_mc: dict = {}
+    for r in await conn.fetch(_REG_SQL):
+        e = by_mc.setdefault(
+            r["mc_uuid"],
+            {"mc_id": r["master_control_id"], "regs": {}})
+        e["regs"][r["reg"]] = r["cnt"]
+    if limit > 0:
+        by_mc = dict(list(by_mc.items())[:limit])
+
+    verif: dict = {}
+    for r in await conn.fetch(_VERIF_SQL):
+        _ucs, m = reg.seed_classify(vmethods=r["vmethods"], etypes=r["etypes"])
+        if m:
+            verif[r["mc_uuid"]] = m
+
+    n_reg = n_uc = n_mc = n_v = 0
+    for mc_uuid, e in by_mc.items():
+        mc_id, regs = e["mc_id"], e["regs"]
+        if not regs:
+            continue
+        primary_reg = max(regs, key=regs.get)
+        uc_primary = reg.use_case_for_regulation(primary_reg)
+        ucs: dict = {}
+        for rg, cnt in regs.items():
+            await conn.execute(
+                """INSERT INTO compliance.mc_regulations
+                   (master_control_uuid, master_control_id, source_regulation,
+                    is_primary, member_count)
+                   VALUES ($1,$2,$3,$4,$5)
+                   ON CONFLICT (master_control_uuid, source_regulation)
+                   DO NOTHING""",
+                mc_uuid, mc_id, rg[:160], rg == primary_reg, cnt)
+            n_reg += 1
+            uc = reg.use_case_for_regulation(rg)
+            if uc:
+                ucs[uc] = ucs.get(uc, False) or (uc == uc_primary)
+        for uc, is_prim in ucs.items():
             await conn.execute(
                 """INSERT INTO compliance.mc_use_case_mappings
                    (master_control_uuid, master_control_id, use_case,
-                    method, confidence, rationale)
-                   VALUES ($1,$2,$3,'seed',0.6,'deterministic seed')
-                   ON CONFLICT (master_control_uuid, use_case) DO NOTHING""",
-                r["mc_uuid"], r["master_control_id"], uc,
-            )
-            n_uc_rows += 1
-        if ucs:
-            n_mc_with_uc += 1
-        if method:
+                    method, confidence, rationale, is_primary)
+                   VALUES ($1,$2,$3,'seed',0.85,'source_regulation',$4)
+                   ON CONFLICT (master_control_uuid, use_case)
+                   DO UPDATE SET is_primary =
+                        mc_use_case_mappings.is_primary OR EXCLUDED.is_primary
+                   WHERE mc_use_case_mappings.method <> 'manual'""",
+                mc_uuid, mc_id, uc, is_prim)
+            n_uc += 1
+        n_mc += 1
+        m = verif.get(mc_uuid)
+        if m:
             await conn.execute(
                 """INSERT INTO compliance.mc_verification
                    (master_control_uuid, master_control_id,
                     verification_method, method, confidence, rationale)
-                   VALUES ($1,$2,$3,'seed',0.6,'deterministic seed')
+                   VALUES ($1,$2,$3,'seed',0.7,'member evidence_type')
                    ON CONFLICT (master_control_uuid) DO NOTHING""",
-                r["mc_uuid"], r["master_control_id"], method,
-            )
-            n_verif += 1
+                mc_uuid, mc_id, m)
+            n_v += 1
+
     total = await conn.fetchval(
         "SELECT count(*) FROM compliance.mc_use_case_mappings")
     await conn.execute(
         """INSERT INTO compliance.mc_use_case_sync_state
            (registry_hash, stage, total_mappings, mcs_classified)
-           VALUES ($1,'seed',$2,$3)""",
-        reg.registry_hash(), total, n_mc_with_uc,
-    )
-    return {"mcs": len(rows), "mcs_with_use_case": n_mc_with_uc,
-            "use_case_rows": n_uc_rows, "verification_rows": n_verif}
+           VALUES ($1,'seed_source_regulation',$2,$3)""",
+        reg.registry_hash(), total, n_mc)
+    return {"mcs_mapped": n_mc, "regulation_rows": n_reg,
+            "use_case_rows": n_uc, "verification_rows": n_v}
 
 
 async def _main() -> None:
     ap = argparse.ArgumentParser()
     ap.add_argument("--limit", type=int, default=0)
     ap.add_argument("--with-llm", action="store_true",
-                    help="Phase 3 — noch nicht implementiert")
+                    help="Fallback fuer MCs ohne source_regulation (TODO)")
     args = ap.parse_args()
     if args.with_llm:
-        raise SystemExit("LLM-Stufe (Phase 3) noch nicht implementiert.")
+        raise SystemExit("LLM-Fallback (Phase 3) noch nicht implementiert.")
     conn = await asyncpg.connect(os.getenv("DATABASE_URL"))
     try:
         stats = await run_seed(conn, args.limit)
     finally:
         await conn.close()
-    print("Seed fertig:", stats)
+    print("Seed (source_regulation) fertig:", stats)
 
 
 if __name__ == "__main__":
diff --git a/backend-compliance/tests/test_use_case_registry.py b/backend-compliance/tests/test_use_case_registry.py
index ba6815ed..09c05fe4 100644
--- a/backend-compliance/tests/test_use_case_registry.py
+++ b/backend-compliance/tests/test_use_case_registry.py
@@ -110,3 +110,38 @@ def test_seed_empty_and_none_safe():
                                vmethods=[None], etypes=[None])
     assert ucs == [] and m is None
     assert reg.seed_classify() == ([], None)
+
+
+# ── Deterministischer Regulierung→Use-Case-Mapper ───────────────────
+
+
+def test_regulation_mapper_known():
+    cases = {
+        "OWASP Top 10 (2021)": "code_security",
+        "NIST SP 800-207 (Zero Trust)": "network_security",
+        "Cyber Resilience Act (CRA)": "cra",
+        "DSGVO (EU) 2016/679": "dse",
+        "EDPB Facial Recognition": "dse",      # Leitlinie → Datenschutz
+        "TKG": "impressum",
+        "TDDDG": "cookie_banner",
+        "Markets in Crypto-Assets (MiCA)": "mica",
+        "BGB": "agb",
+    }
+    for reg_str, expected in cases.items():
+        assert reg.use_case_for_regulation(reg_str) == expected, reg_str
+
+
+def test_regulation_mapper_abgb_before_bgb():
+    # 'ABGB' enthaelt 'bgb' — die abgb-Regel MUSS zuerst greifen.
+    assert reg.use_case_for_regulation("AT ABGB") == "handelsrecht"
+
+
+def test_regulation_mapper_unknown_returns_none():
+    assert reg.use_case_for_regulation("Voellig Unbekanntes Gesetz") is None
+    assert reg.use_case_for_regulation(None) is None
+
+
+def test_all_regulation_rules_point_to_valid_use_cases():
+    for _needle, uc in reg._REGULATION_RULES:
+        assert uc in reg.REGISTRY, uc
+        assert reg.REGISTRY[uc].enabled