diff --git a/profiling/seed.py b/profiling/seed.py
index cf167fa38..1bf68ff55 100644
--- a/profiling/seed.py
+++ b/profiling/seed.py
@@ -10,6 +10,7 @@ from django.contrib.auth.models import Group
 from django.contrib.auth.models import User
 from guardian.shortcuts import assign_perm
 
+from documents.models import Document
 from documents.tests.factories import CorrespondentFactory
 from documents.tests.factories import DocumentFactory
 from documents.tests.factories import DocumentTypeFactory
@@ -18,13 +19,17 @@ from documents.tests.factories import TagFactory
 
 if TYPE_CHECKING:
     from documents.models import Correspondent
-    from documents.models import Document
     from documents.models import DocumentType
     from documents.models import StoragePath
     from documents.models import Tag
 
 ScaleProfile = Literal["medium", "large"]
 
+# Fraction of seeded documents given a real owner; the remainder stays
+# owner=None, mirroring a real install's mix of owned and legacy/imported
+# unowned documents.
+_OWNED_FRACTION = 0.9
+
 
 class _ScaleCounts:
     __slots__ = (
@@ -140,7 +145,20 @@ def seed_permission_dataset(
     for user in users:
         user.groups.add(rng.choice(groups))
 
-    documents = tuple(DocumentFactory.create_batch(counts.documents))
+    documents = list(DocumentFactory.create_batch(counts.documents))
+
+    # Assign realistic ownership -- without this, every document stays
+    # owner=None and the "owned or unowned" visibility clause is trivially
+    # true for every row, so no guardian permission check ever needs to run
+    # (see the amendment note above this code block).
+    owned_documents = []
+    for document in documents:
+        if rng.random() < _OWNED_FRACTION:
+            document.owner = rng.choice(users)
+            owned_documents.append(document)
+    Document.objects.bulk_update(owned_documents, ["owner"], batch_size=2_000)
+    documents = tuple(documents)
+
     tags = tuple(TagFactory.create_batch(counts.tags))
     correspondents = tuple(CorrespondentFactory.create_batch(counts.correspondents))
     document_types = tuple(DocumentTypeFactory.create_batch(counts.document_types))
@@ -149,29 +167,26 @@ def seed_permission_dataset(
     n_user_perms = round(counts.documents * _USER_PERM_ROWS_PER_DOC)
     n_group_perms = round(counts.documents * _GROUP_PERM_ROWS_PER_DOC)
 
-    # guardian's assign_perm is a get_or_create on the (subject, object,
-    # permission) triple, so drawing (subject, document) pairs *with*
-    # replacement -- rng.choice/rng.choice in a loop -- collides far more
-    # than the raw draw count suggests once the subject pool is small
-    # relative to the number of draws (a birthday-paradox effect): e.g. at
-    # medium scale, 45,387 draws over only 5 groups x 20,000 documents =
-    # 100,000 slots yields ~36,500 *distinct* pairs, not ~45,387. Sampling
-    # distinct pairs up front guarantees the seeded row counts actually
-    # land on the real-install ratios the scale profiles are derived from.
-    for user_idx, doc_idx in _sample_distinct_pairs(
+    # Grant permissions only on OWNED documents -- a grant on an already-
+    # unowned document is a no-op for visibility (unowned documents are
+    # visible to everyone regardless), so restricting the pool here is what
+    # makes each assign_perm() call actually matter for someone, and is
+    # what exercises the guardian-permission-join code path this profiling
+    # effort exists to measure.
+    for user_idx, owned_idx in _sample_distinct_pairs(
         rng,
         len(users),
-        len(documents),
+        len(owned_documents),
         n_user_perms,
     ):
-        assign_perm("view_document", users[user_idx], documents[doc_idx])
-    for group_idx, doc_idx in _sample_distinct_pairs(
+        assign_perm("view_document", users[user_idx], owned_documents[owned_idx])
+    for group_idx, owned_idx in _sample_distinct_pairs(
         rng,
         len(groups),
-        len(documents),
+        len(owned_documents),
         n_group_perms,
     ):
-        assign_perm("view_document", groups[group_idx], documents[doc_idx])
+        assign_perm("view_document", groups[group_idx], owned_documents[owned_idx])
 
     return SeededData(
         users=users,