diff --git a/fusion_accounting_core/models/__init__.py b/fusion_accounting_core/models/__init__.py
index 8e2d2d1b..bcc7bba4 100644
--- a/fusion_accounting_core/models/__init__.py
+++ b/fusion_accounting_core/models/__init__.py
@@ -1 +1,3 @@
 from . import ir_module_module
+from . import account_move
+from . import account_reconcile_model
diff --git a/fusion_accounting_core/models/account_move.py b/fusion_accounting_core/models/account_move.py
new file mode 100644
index 00000000..e4dd1c94
--- /dev/null
+++ b/fusion_accounting_core/models/account_move.py
@@ -0,0 +1,56 @@
+"""Shared-field-ownership declarations for account.move.
+
+Per the roadmap (Section 3.3), these fields exist in Odoo Enterprise's
+account_accountant module. By declaring them here with identical schemas
+and identical relation tables, fusion_accounting_core becomes a co-owner.
+When Enterprise uninstalls, Odoo's module registry sees fusion still owns
+the fields and preserves the columns / relation tables, so the data
+(deferred revenue links, signing user, etc.) survives uninstall.
+
+The fields here have NO compute methods, NO defaults beyond what Enterprise
+provides, NO views. They're pure schema-preservation declarations. Any
+business logic that operates on these fields lives in Enterprise (when
+present) or in a future fusion sub-module that opts to own that behavior.
+"""
+
+from odoo import fields, models
+
+
+class AccountMove(models.Model):
+    _inherit = "account.move"
+
+    deferred_move_ids = fields.Many2many(
+        comodel_name='account.move',
+        relation='account_move_deferred_rel',
+        column1='original_move_id',
+        column2='deferred_move_id',
+        copy=False,
+        string="Deferred Entries",
+    )
+    deferred_original_move_ids = fields.Many2many(
+        comodel_name='account.move',
+        relation='account_move_deferred_rel',
+        column1='deferred_move_id',
+        column2='original_move_id',
+        copy=False,
+        string="Original Invoices",
+    )
+    deferred_entry_type = fields.Selection(
+        selection=[
+            ('expense', 'Deferred Expense'),
+            ('revenue', 'Deferred Revenue'),
+        ],
+        copy=False,
+        string="Deferred Entry Type",
+    )
+
+    signing_user = fields.Many2one(
+        comodel_name='res.users',
+        copy=False,
+        string="Signing User",
+    )
+
+    payment_state_before_switch = fields.Char(
+        copy=False,
+        string="Payment State Before Switch",
+    )
diff --git a/fusion_accounting_core/models/account_reconcile_model.py b/fusion_accounting_core/models/account_reconcile_model.py
new file mode 100644
index 00000000..4f35c837
--- /dev/null
+++ b/fusion_accounting_core/models/account_reconcile_model.py
@@ -0,0 +1,17 @@
+"""Shared-field-ownership for account.reconcile.model.
+
+Mirrors the single field Enterprise's account_accountant adds to the
+Community account.reconcile.model: created_automatically.
+"""
+
+from odoo import fields, models
+
+
+class AccountReconcileModel(models.Model):
+    _inherit = "account.reconcile.model"
+
+    created_automatically = fields.Boolean(
+        default=False,
+        copy=False,
+        string="Created Automatically",
+    )
diff --git a/fusion_accounting_core/tests/__init__.py b/fusion_accounting_core/tests/__init__.py
index f1a2b5c5..10b90050 100644
--- a/fusion_accounting_core/tests/__init__.py
+++ b/fusion_accounting_core/tests/__init__.py
@@ -1 +1,2 @@
 from . import test_enterprise_detection
+from . import test_shared_field_ownership
diff --git a/fusion_accounting_core/tests/test_shared_field_ownership.py b/fusion_accounting_core/tests/test_shared_field_ownership.py
new file mode 100644
index 00000000..82fb24e1
--- /dev/null
+++ b/fusion_accounting_core/tests/test_shared_field_ownership.py
@@ -0,0 +1,32 @@
+from odoo.tests.common import TransactionCase, tagged
+
+
+@tagged('post_install', '-at_install')
+class TestSharedFieldOwnership(TransactionCase):
+    """Verify fusion_accounting_core declares the Enterprise extension fields
+    on account.move and account.reconcile.model, so they survive Enterprise uninstall."""
+
+    def test_account_move_deferred_fields_exist(self):
+        Move = self.env['account.move']
+        for fname in ('deferred_move_ids', 'deferred_original_move_ids', 'deferred_entry_type'):
+            self.assertIn(fname, Move._fields, f"{fname!r} must exist on account.move")
+
+    def test_account_move_signing_user_exists(self):
+        Move = self.env['account.move']
+        self.assertIn('signing_user', Move._fields)
+
+    def test_account_move_payment_state_before_switch_exists(self):
+        Move = self.env['account.move']
+        self.assertIn('payment_state_before_switch', Move._fields)
+
+    def test_account_reconcile_model_created_automatically_exists(self):
+        Model = self.env['account.reconcile.model']
+        self.assertIn('created_automatically', Model._fields)
+
+    def test_deferred_relation_table_name_matches_enterprise(self):
+        """The shared M2M relation table must be named identically to Enterprise's
+        so dual ownership works (Enterprise drops field => fusion preserves table)."""
+        f = self.env['account.move']._fields['deferred_move_ids']
+        self.assertEqual(f.relation, 'account_move_deferred_rel')
+        self.assertEqual(f.column1, 'original_move_id')
+        self.assertEqual(f.column2, 'deferred_move_id')