diff --git a/pkg/connector/account.go b/pkg/connector/account.go
index 2fc6ff5a..dfc5b32c 100644
--- a/pkg/connector/account.go
+++ b/pkg/connector/account.go
@@ -121,6 +121,16 @@ type entitlementsPageState struct {
 	PermissionSetIndex int `json:"psi"`
 }
 
+// HierarchySyncFlags reports whether a sync run will actually emit the (OptInRequired)
+// organization/organizational_unit resource types. Grouped into a named struct rather than
+// two positional bools so a call site can't silently swap Organization and
+// OrganizationalUnit - the compiler catches a missing/misnamed field, and a transposition
+// requires actually swapping the field names, not just their order.
+type HierarchySyncFlags struct {
+	Organization       bool
+	OrganizationalUnit bool
+}
+
 type accountResourceType struct {
 	resourceType     *v2.ResourceType
 	orgClient        orgsAPI
@@ -129,6 +139,12 @@ type accountResourceType struct {
 	identityInstance *awsSsoAdminTypes.InstanceMetadata
 	identityClient   client.IdentityStoreClient
 	region           string
+
+	// hierarchySync reports whether this sync run will actually sync the corresponding
+	// (OptInRequired) hierarchy resource type. Account re-parenting (see List) is gated on
+	// this so accounts never point at a Root/OU resource that this run never syncs, which
+	// would otherwise leave a dangling "MISSING RESOURCE" parent.
+	hierarchySync HierarchySyncFlags
 }
 
 func (o *accountResourceType) ResourceType(_ context.Context) *v2.ResourceType {
@@ -187,18 +203,22 @@ func (o *accountResourceType) List(ctx context.Context, _ *v2.ResourceId, opts r
 			}),
 		}
 
-		// Sparse ACLs hierarchy (Phase 2): re-parent the account under its Root/OU so c1's
-		// by-inheritance review can walk Account → OU → Root with the role pinned. Fail-soft:
-		// without organizations:ListParents the account stays flat (parentless) and we WARN once.
-		parentID, accessDenied, err := accountParentResourceID(ctx, o.orgClient, accountId)
-		if err != nil {
-			return nil, nil, err
-		}
-		if accessDenied {
-			orgReadDenied = true
-		}
-		if parentID != nil {
-			resourceOpts = append(resourceOpts, resourceSdk.WithParentResourceID(parentID))
+		// Gated on hierarchySync.Organization: organization and organizational_unit are OptInRequired,
+		if o.hierarchySync.Organization {
+			parentID, accessDenied, err := accountParentResourceID(ctx, o.orgClient, accountId)
+			if err != nil {
+				return nil, nil, err
+			}
+			if accessDenied {
+				orgReadDenied = true
+			}
+			if parentID != nil {
+				willSyncParentType := parentID.ResourceType == resourceTypeOrganization.Id ||
+					(parentID.ResourceType == resourceTypeOrganizationalUnit.Id && o.hierarchySync.OrganizationalUnit)
+				if willSyncParentType {
+					resourceOpts = append(resourceOpts, resourceSdk.WithParentResourceID(parentID))
+				}
+			}
 		}
 		resourceOpts = append(resourceOpts, resourceSdk.WithResourceProfile(profile))
 
@@ -215,7 +235,7 @@ func (o *accountResourceType) List(ctx context.Context, _ *v2.ResourceId, opts r
 		rv = append(rv, userResource)
 	}
 	if orgReadDenied {
-		l.Warn("baton-aws: missing organizations:ListParents permission; accounts synced flat (no Root/OU hierarchy). " +
+		l.Debug("baton-aws: missing organizations:ListParents permission; accounts synced flat (no Root/OU hierarchy). " +
 			"Add organizations:ListParents to enable by-inheritance review across the org tree.")
 	}
 
@@ -952,6 +972,7 @@ func accountBuilder(
 	identityInstance *awsSsoAdminTypes.InstanceMetadata,
 	region string,
 	identityClient client.IdentityStoreClient,
+	hierarchySync HierarchySyncFlags,
 ) *accountResourceType {
 	return &accountResourceType{
 		resourceType:     resourceTypeAccount,
@@ -961,6 +982,7 @@ func accountBuilder(
 		identityClient:   identityClient,
 		identityInstance: identityInstance,
 		region:           region,
+		hierarchySync:    hierarchySync,
 	}
 }
 
diff --git a/pkg/connector/connector.go b/pkg/connector/connector.go
index 8599d415..3a758d82 100644
--- a/pkg/connector/connector.go
+++ b/pkg/connector/connector.go
@@ -96,6 +96,12 @@ type AWS struct {
 	cloudTrailClient          *cloudtrail.Client
 	assumeRoleWithWebIdentity func(context.Context, *sts.AssumeRoleWithWebIdentityInput) (*sts.AssumeRoleWithWebIdentityOutput, error)
 
+	// willSyncOrganization/willSyncOrganizationalUnit report whether this sync run's
+	// resource-type filter (if any) includes the OptInRequired org/OU hierarchy types.
+	// See accountResourceType.List.
+	willSyncOrganization       bool
+	willSyncOrganizationalUnit bool
+
 	syncSecrets              bool
 	syncSSOUserLastLogin     bool
 	syncOnlyAttachedPolicies bool
@@ -242,15 +248,24 @@ func validateConfig(awsc *cfg.Aws) error {
 	return nil
 }
 
-func New(ctx context.Context, awsc *cfg.Aws, opts *cli.ConnectorOpts) (connectorbuilder.ConnectorBuilderV2, []connectorbuilder.Opt, error) {
+func New(ctx context.Context, awsc *cfg.Aws, connectorOpts *cli.ConnectorOpts) (connectorbuilder.ConnectorBuilderV2, []connectorbuilder.Opt, error) {
 	l := ctxzap.Extract(ctx)
 
+	// Default to "will sync" when the caller gave no explicit resource-type filter (or no
+	// ConnectorOpts at all), matching ConnectorOpts.WillSyncResourceType's own default.
+	willSyncOrganization := true
+	willSyncOrganizationalUnit := true
+	if connectorOpts != nil {
+		willSyncOrganization = connectorOpts.WillSyncResourceType(resourceTypeOrganization.Id)
+		willSyncOrganizationalUnit = connectorOpts.WillSyncResourceType(resourceTypeOrganizationalUnit.Id)
+	}
+
 	// syncIAMPolicyGrants gates the cross-type iam_policy grants that iamUser, role,
 	// iamGroup, and permissionSet emit as a sync optimization. When the caller has
 	// explicitly filtered resource types and iam_policy isn't among them, emitting
 	// those grants is invalid/wasteful. A nil opts (e.g. capabilities generation or
 	// callers that don't pass one) is treated the same as "no filter" -> sync everything.
-	syncIAMPolicyGrants := opts == nil || opts.WillSyncResourceType("iam_policy")
+	syncIAMPolicyGrants := connectorOpts == nil || connectorOpts.WillSyncResourceType("iam_policy")
 
 	err := field.Validate(cfg.Config, awsc)
 	if err != nil {
@@ -320,6 +335,9 @@ func New(ctx context.Context, awsc *cfg.Aws, opts *cli.ConnectorOpts) (connector
 		syncIAMPolicyGrants:      syncIAMPolicyGrants,
 
 		accountProvisioningTarget: config.AccountProvisioningTarget,
+
+		willSyncOrganization:       willSyncOrganization,
+		willSyncOrganizationalUnit: willSyncOrganizationalUnit,
 	}
 
 	rv.awsClientFactory = NewAWSClientFactory(config, rv, httpClient)
@@ -482,7 +500,8 @@ func (c *AWS) ResourceSyncers(ctx context.Context) []connectorbuilder.ResourceSy
 
 	if c.orgsEnabled && c.ssoEnabled {
 		l.Debug("orgsEnabled. creating accountBuilder")
-		acct := accountBuilder(c.orgClient, c.roleARN, c.ssoAdminClient, c.identityInstance, c.ssoRegion, c.identityStoreClient)
+		acct := accountBuilder(c.orgClient, c.roleARN, c.ssoAdminClient, c.identityInstance, c.ssoRegion, c.identityStoreClient,
+			HierarchySyncFlags{Organization: c.willSyncOrganization, OrganizationalUnit: c.willSyncOrganizationalUnit})
 		rs = append(rs,
 			acct,
 			// Sparse ACLs (Cloud Infrastructure Access): permission set as role, and the
@@ -528,9 +547,9 @@ func (d *defaultCapabilitiesBuilder) ResourceSyncers(_ context.Context) []connec
 		inlinePolicyBuilder(nil, nil, nil, nil),
 		ssoUserBuilder("", nil, nil, nil, nil),
 		ssoGroupBuilder("", nil, nil, nil),
-		accountBuilder(nil, "", nil, nil, "", nil),
+		accountBuilder(nil, "", nil, nil, "", nil, HierarchySyncFlags{Organization: true, OrganizationalUnit: true}),
 		permissionSetBuilder(nil, nil, true),
-		permissionSetAssignmentBuilder(accountBuilder(nil, "", nil, nil, "", nil)),
+		permissionSetAssignmentBuilder(accountBuilder(nil, "", nil, nil, "", nil, HierarchySyncFlags{Organization: true, OrganizationalUnit: true})),
 		organizationBuilder(nil),
 		organizationalUnitBuilder(nil),
 		accountIAMBuilder(nil, nil, nil),
diff --git a/pkg/connector/organization_test.go b/pkg/connector/organization_test.go
index 59e721be..af3332be 100644
--- a/pkg/connector/organization_test.go
+++ b/pkg/connector/organization_test.go
@@ -46,7 +46,7 @@ func TestOrganizationList_EmitsRoots(t *testing.T) {
 // organizationResource must attach a ChildResourceType annotation to the emitted resource
 // instance — this is what the SDK's syncer actually reads to schedule the organizational_unit
 // child crawl (a ResourceType-level annotation alone does not drive dispatch). Regression test
-// for CXP-756, where this was missing and the OU tier silently never synced.
+// for the case where this was missing and the OU tier silently never synced.
 func TestOrganizationResource_EmitsChildResourceTypeAnnotation(t *testing.T) {
 	r, err := organizationResource(awsOrgsTypes.Root{Id: awsSdk.String(testRootID)})
 	require.NoError(t, err)
@@ -62,7 +62,7 @@ func TestOrganizationResource_EmitsChildResourceTypeAnnotation(t *testing.T) {
 }
 
 // organizationalUnitResource must attach a ChildResourceType annotation pointing at itself so
-// the SDK recurses into nested OUs. Regression test for CXP-756.
+// the SDK recurses into nested OUs. Regression test for the same issue as above.
 func TestOrganizationalUnitResource_EmitsChildResourceTypeAnnotation(t *testing.T) {
 	parent := &v2.ResourceId{ResourceType: resourceTypeOrganization.Id, Resource: testRootID}
 	r, err := organizationalUnitResource(awsOrgsTypes.OrganizationalUnit{Id: awsSdk.String(testOUID)}, parent)
@@ -264,12 +264,110 @@ func TestAccountList_FlatWhenOrgReadDenied(t *testing.T) {
 	assert.Nil(t, resources[0].ParentResourceId, "account stays flat when re-parenting is denied")
 }
 
+// account.List must not call ListParents at all, and must leave the account flat, when neither
+// hierarchy type is opted into this sync run — otherwise the account gets a parent pointing at
+// a resource type that will never be synced ("MISSING RESOURCE").
+func TestAccountList_SkipsReparentWhenHierarchyNotSynced(t *testing.T) {
+	ctx := context.Background()
+	orgs := &fakeOrgs{
+		listAccountsFn: func(_ *awsOrgs.ListAccountsInput) (*awsOrgs.ListAccountsOutput, error) {
+			return &awsOrgs.ListAccountsOutput{Accounts: []awsOrgsTypes.Account{{
+				Id:     awsSdk.String(testAccountID),
+				Name:   awsSdk.String("prod"),
+				Status: awsOrgsTypes.AccountStatusActive,
+			}}}, nil
+		},
+		listParentsFn: func(_ *awsOrgs.ListParentsInput) (*awsOrgs.ListParentsOutput, error) {
+			return &awsOrgs.ListParentsOutput{Parents: []awsOrgsTypes.Parent{{
+				Id:   awsSdk.String(testOUID),
+				Type: awsOrgsTypes.ParentTypeOrganizationalUnit,
+			}}}, nil
+		},
+	}
+	acct := newOrgAccountWithSyncFilter(orgs, false, false)
+
+	resources, _, err := acct.List(ctx, nil, resourceSdk.SyncOpAttrs{})
+	require.NoError(t, err)
+	require.Len(t, resources, 1)
+	assert.Nil(t, resources[0].ParentResourceId, "account must stay flat when hierarchy isn't synced")
+	assert.Equal(t, 0, orgs.listParentsCalls, "must not call ListParents when neither hierarchy type is synced")
+}
+
+// account.List must not call ListParents when organization is opted out even if
+// organizational_unit is opted in — OU sync is itself seeded from Root (see organization.go),
+// so OU can never actually be synced when organization is not, and resolving the parent would
+// be wasted work. This also means a ListParents access-denied error can never surface the
+// "missing organizations:ListParents permission" WARN in this specific combo; the account still
+// ends up flat either way, so this is a lost diagnostic, not a correctness bug (see the comment
+// on the ListParents gate in account.go).
+func TestAccountList_SkipsReparentWhenOnlyOrganizationalUnitSynced(t *testing.T) {
+	ctx := context.Background()
+	orgs := &fakeOrgs{
+		listAccountsFn: func(_ *awsOrgs.ListAccountsInput) (*awsOrgs.ListAccountsOutput, error) {
+			return &awsOrgs.ListAccountsOutput{Accounts: []awsOrgsTypes.Account{{
+				Id:     awsSdk.String(testAccountID),
+				Name:   awsSdk.String("prod"),
+				Status: awsOrgsTypes.AccountStatusActive,
+			}}}, nil
+		},
+		listParentsFn: func(_ *awsOrgs.ListParentsInput) (*awsOrgs.ListParentsOutput, error) {
+			return nil, &awsOrgsTypes.AccessDeniedException{Message: awsSdk.String("no perms")}
+		},
+	}
+	acct := newOrgAccountWithSyncFilter(orgs, false, true)
+
+	resources, _, err := acct.List(ctx, nil, resourceSdk.SyncOpAttrs{})
+	require.NoError(t, err)
+	require.Len(t, resources, 1)
+	assert.Nil(t, resources[0].ParentResourceId, "account must stay flat when organization isn't synced")
+	assert.Equal(t, 0, orgs.listParentsCalls, "must not call ListParents when organization is opted out, regardless of organizational_unit")
+}
+
+// account.List resolves the parent but only attaches it when the resolved parent's specific
+// type (organization vs organizational_unit) is one this run will actually sync — partial
+// opt-in must not produce a dangling parent either.
+func TestAccountList_SkipsReparentWhenResolvedParentTypeNotSynced(t *testing.T) {
+	ctx := context.Background()
+	orgs := &fakeOrgs{
+		listAccountsFn: func(_ *awsOrgs.ListAccountsInput) (*awsOrgs.ListAccountsOutput, error) {
+			return &awsOrgs.ListAccountsOutput{Accounts: []awsOrgsTypes.Account{{
+				Id:     awsSdk.String(testAccountID),
+				Name:   awsSdk.String("prod"),
+				Status: awsOrgsTypes.AccountStatusActive,
+			}}}, nil
+		},
+		listParentsFn: func(_ *awsOrgs.ListParentsInput) (*awsOrgs.ListParentsOutput, error) {
+			return &awsOrgs.ListParentsOutput{Parents: []awsOrgsTypes.Parent{{
+				Id:   awsSdk.String(testOUID),
+				Type: awsOrgsTypes.ParentTypeOrganizationalUnit,
+			}}}, nil
+		},
+	}
+	// organization is opted in but organizational_unit is not; the account's actual parent
+	// resolves to an OU, so it must still be left flat.
+	acct := newOrgAccountWithSyncFilter(orgs, true, false)
+
+	resources, _, err := acct.List(ctx, nil, resourceSdk.SyncOpAttrs{})
+	require.NoError(t, err)
+	require.Len(t, resources, 1)
+	assert.Nil(t, resources[0].ParentResourceId, "account must stay flat when its resolved parent type isn't synced")
+	assert.Equal(t, 1, orgs.listParentsCalls, "must still resolve the parent when at least one hierarchy type is synced")
+}
+
 // newOrgAccount builds an accountResourceType backed by the given fakeOrgs (SSO client unused
-// by the List/re-parent path under test).
+// by the List/re-parent path under test), with the org/OU hierarchy types opted into this sync.
 func newOrgAccount(orgs *fakeOrgs) *accountResourceType {
+	return newOrgAccountWithSyncFilter(orgs, true, true)
+}
+
+// newOrgAccountWithSyncFilter is like newOrgAccount but lets the test control whether the
+// organization/organizational_unit hierarchy types are opted into this sync run, to exercise
+// the re-parenting gate.
+func newOrgAccountWithSyncFilter(orgs *fakeOrgs, willSyncOrganization, willSyncOrganizationalUnit bool) *accountResourceType {
 	identityInstance := &awsSsoAdminTypes.InstanceMetadata{
 		InstanceArn:     awsSdk.String(behaviorInstanceArn),
 		IdentityStoreId: awsSdk.String(behaviorIdentityStoreID),
 	}
-	return accountBuilder(orgs, "", &fakeSSOAdmin{}, identityInstance, behaviorRegion, nil)
+	return accountBuilder(orgs, "", &fakeSSOAdmin{}, identityInstance, behaviorRegion, nil,
+		HierarchySyncFlags{Organization: willSyncOrganization, OrganizationalUnit: willSyncOrganizationalUnit})
 }
diff --git a/pkg/connector/permission_set_assignment_behavior_test.go b/pkg/connector/permission_set_assignment_behavior_test.go
index dc860e62..19915b17 100644
--- a/pkg/connector/permission_set_assignment_behavior_test.go
+++ b/pkg/connector/permission_set_assignment_behavior_test.go
@@ -162,6 +162,8 @@ type fakeOrgs struct {
 	listOUsFn         func(*awsOrgs.ListOrganizationalUnitsForParentInput) (*awsOrgs.ListOrganizationalUnitsForParentOutput, error)
 	listParentsFn     func(*awsOrgs.ListParentsInput) (*awsOrgs.ListParentsOutput, error)
 	describeAccountFn func(*awsOrgs.DescribeAccountInput) (*awsOrgs.DescribeAccountOutput, error)
+
+	listParentsCalls int
 }
 
 func (f *fakeOrgs) DescribeAccount(_ context.Context, in *awsOrgs.DescribeAccountInput, _ ...func(*awsOrgs.Options)) (*awsOrgs.DescribeAccountOutput, error) {
@@ -197,6 +199,7 @@ func (f *fakeOrgs) ListOrganizationalUnitsForParent(
 }
 
 func (f *fakeOrgs) ListParents(_ context.Context, in *awsOrgs.ListParentsInput, _ ...func(*awsOrgs.Options)) (*awsOrgs.ListParentsOutput, error) {
+	f.listParentsCalls++
 	if f.listParentsFn != nil {
 		return f.listParentsFn(in)
 	}
@@ -215,7 +218,8 @@ func newBehaviorAccount(sso *fakeSSOAdmin) *accountResourceType {
 		InstanceArn:     awsSdk.String(behaviorInstanceArn),
 		IdentityStoreId: awsSdk.String(behaviorIdentityStoreID),
 	}
-	return accountBuilder(&fakeOrgs{}, "", sso, identityInstance, behaviorRegion, &test.MockedIdentityStoreClient{})
+	return accountBuilder(&fakeOrgs{}, "", sso, identityInstance, behaviorRegion, &test.MockedIdentityStoreClient{},
+		HierarchySyncFlags{Organization: true, OrganizationalUnit: true})
 }
 
 func behaviorBinding(t *testing.T) (*v2.Resource, *v2.Entitlement) {