diff --git a/src/food-market.api/Controllers/SuperAdmin/SuperAdminOrganizationsController.cs b/src/food-market.api/Controllers/SuperAdmin/SuperAdminOrganizationsController.cs
index c7e0ed4..158fa36 100644
--- a/src/food-market.api/Controllers/SuperAdmin/SuperAdminOrganizationsController.cs
+++ b/src/food-market.api/Controllers/SuperAdmin/SuperAdminOrganizationsController.cs
@@ -234,7 +234,8 @@ public async Task<IActionResult> ChangeOwner(Guid id, [FromBody] ChangeOwnerRequ
     {
         var o = await _db.Organizations.IgnoreQueryFilters().FirstOrDefaultAsync(x => x.Id == id, ct);
         if (o is null) return NotFound();
-        if (string.IsNullOrWhiteSpace(req.Reason)) return BadRequest(new { error = "Reason required." });
+        if (string.IsNullOrWhiteSpace(req.Reason) || req.Reason.Trim().Length < 10)
+            return BadRequest(new { error = "Причина смены владельца обязательна (≥ 10 символов) — она пишется в журнал аудита." });
         var user = await _userMgr.FindByIdAsync(req.NewOwnerUserId.ToString());
         if (user is null || user.OrganizationId != o.Id)
             return BadRequest(new { error = "Пользователь не найден или не принадлежит этой организации." });