diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index 0b1a9ca5fdf..315b0f0d568 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -2326,9 +2326,10 @@ class MailThread(models.AbstractModel):
             if add_sign:
                 signature = "<p>-- <br/>%s</p>" % author.name
 
-        # use company switcher company if author is current user
-        user_company = self.env.company if self.env.user == user else user.company_id
-        company = self.company_id.sudo() if self and 'company_id' in self else user_company
+        # company value should fall back on env.company if:
+        # - no company_id field on record
+        # - company_id field available but not set
+        company = self.company_id.sudo() if self and 'company_id' in self and self.company_id else self.env.company
         if company.website:
             website_url = 'http://%s' % company.website if not company.website.lower().startswith(('http:', 'https:')) else company.website
         else:
diff --git a/addons/test_mail/tests/test_message_post.py b/addons/test_mail/tests/test_message_post.py
index 6ef40ab3c09..9b715b6d2f6 100644
--- a/addons/test_mail/tests/test_message_post.py
+++ b/addons/test_mail/tests/test_message_post.py
@@ -12,6 +12,7 @@ from odoo.api import call_kw
 from odoo.exceptions import AccessError
 from odoo.tests import tagged
 from odoo.tools import mute_logger, formataddr
+from odoo.tests.common import users
 
 
 @tagged('mail_post')
@@ -35,6 +36,43 @@ class TestMessagePost(TestMailCommon, TestRecipients):
         messageId = call_kw(self.env['mail.channel'], 'message_post', [test_channel.id], {'body': 'test'})
         self.assertTrue(isinstance(messageId, int))
 
+    @users('employee')
+    def test_notify_prepare_template_context_company_value(self):
+        """ Verify that the template context company value is right
+        after switching the env company or if a company_id is set
+        on mail record.
+        """
+        current_user = self.env.user
+        main_company = current_user.company_id
+        other_company = self.env['res.company'].with_user(self.user_admin).create({'name': 'Company B'})
+        current_user.sudo().write({'company_ids': [(4, other_company.id)]})
+        test_record = self.env['mail.test.multi.company'].with_user(self.user_admin).create({
+            'name': 'Multi Company Record',
+            'company_id': False,
+        })
+
+        # self.env.company.id = Main Company    AND    test_record.company_id = False
+        self.assertEqual(self.env.company.id, main_company.id)
+        self.assertEqual(test_record.company_id.id, False)
+        template_values = test_record._notify_prepare_template_context(test_record.message_ids, {})
+        self.assertEqual(template_values.get('company').id, self.env.company.id)
+
+        # self.env.company.id = Other Company    AND    test_record.company_id = False
+        current_user.company_id = other_company
+        test_record = self.env['mail.test.multi.company'].browse(test_record.id)
+        self.assertEqual(self.env.company.id, other_company.id)
+        self.assertEqual(test_record.company_id.id, False)
+        template_values = test_record._notify_prepare_template_context(test_record.message_ids, {})
+        self.assertEqual(template_values.get('company').id, self.env.company.id)
+
+        # self.env.company.id = Other Company    AND    test_record.company_id = Main Company
+        test_record.company_id = main_company
+        test_record = self.env['mail.test.multi.company'].browse(test_record.id)
+        self.assertEqual(self.env.company.id, other_company.id)
+        self.assertEqual(test_record.company_id.id, main_company.id)
+        template_values = test_record._notify_prepare_template_context(test_record.message_ids, {})
+        self.assertEqual(template_values.get('company').id, main_company.id)
+
     def test_notify_recipients_internals(self):
         pdata = self._generate_notify_recipients(self.partner_1 | self.partner_employee)
         msg_vals = {