diff --git a/app/services/data_import.py b/app/services/data_import.py
index 7fbfb5e..11f1adf 100644
--- a/app/services/data_import.py
+++ b/app/services/data_import.py
@@ -94,9 +94,11 @@ class SourceImporter(Protocol):
         """Run the source's validation gates against ``staged``. Read-only."""
         ...
 
-    async def promote(self, db: AsyncSession, staged: Any) -> dict[str, int]:
+    async def promote(self, db: AsyncSession, staged: Any, run_id: int) -> dict[str, int]:
         """Apply ``staged`` to the live tables. Called inside the promotion
-        transaction; the caller commits. Returns row-count deltas."""
+        transaction; the caller commits. ``run_id`` is the current
+        ``data_import_runs.id`` so written rows can be stamped with their
+        ``import_run_id``. Returns row-count deltas."""
         ...
 
 
@@ -213,7 +215,7 @@ async def run_import(
                     return run
 
                 # Promotion: importer writes + run-row flip in one transaction.
-                row_counts = await importer.promote(session, staged)
+                row_counts = await importer.promote(session, staged, run.id)
                 run.status = STATUS_PROMOTED
                 run.row_counts_json = json.dumps(row_counts, default=str)
                 run.completed_at = _now()
diff --git a/tests/unit/test_data_import_framework.py b/tests/unit/test_data_import_framework.py
index 67b200c..02a60a8 100644
--- a/tests/unit/test_data_import_framework.py
+++ b/tests/unit/test_data_import_framework.py
@@ -96,18 +96,19 @@ class FakeImporter:
             messages=[] if self.ok else ["coverage below threshold"],
         )
 
-    async def promote(self, db, staged):
+    async def promote(self, db, staged, run_id):
         if self.raise_in == "promote":
             # write one row THEN raise, to prove rollback undoes partial writes
             db.add(_snapshot(self.revision, 999))
             raise RuntimeError("boom-promote")
         for i in staged:
-            db.add(_snapshot(self.revision, i))
+            db.add(_snapshot(self.revision, i, run_id=run_id))
         self.promoted = True
+        self.promoted_run_id = run_id
         return {"fundamental_snapshots": len(staged)}
 
 
-def _snapshot(revision: str, i: int) -> FundamentalSnapshot:
+def _snapshot(revision: str, i: int, run_id: int | None = None) -> FundamentalSnapshot:
     return FundamentalSnapshot(
         cik=f"{i:010d}",
         accession=f"{revision}-{i:06d}",
@@ -118,6 +119,7 @@ def _snapshot(revision: str, i: int) -> FundamentalSnapshot:
         fiscal_year=2026,
         fiscal_period="Q2",
         revenue=1000.0 + i,
+        import_run_id=run_id,
     )
 
 
@@ -154,6 +156,12 @@ async def test_promote_writes_and_records_run(engine):
     assert run.source_max_date == date(2026, 7, 21)
     assert run.completed_at is not None
     assert await _count(factory, FundamentalSnapshot) == 4
+    # rows stamped with the run id
+    async with factory() as s:
+        stamped = (
+            await s.execute(select(FundamentalSnapshot.import_run_id))
+        ).scalars().all()
+    assert stamped and all(rid == run.id for rid in stamped)
 
 
 async def test_no_op_on_repeated_revision(engine):