diff --git a/AyCode.Core/Interfaces/ICompanyInfoBase.cs b/AyCode.Core/Interfaces/ICompanyInfoBase.cs
index 5f4c272..43e7168 100644
--- a/AyCode.Core/Interfaces/ICompanyInfoBase.cs
+++ b/AyCode.Core/Interfaces/ICompanyInfoBase.cs
@@ -9,7 +9,7 @@ namespace AyCode.Core.Interfaces;
 public interface ICompanyInfoBase
 {
     string Name { get; }
-    string TaxId { get; }
+    string? TaxId { get; }
     string CountryCode { get; }
     string PostalCode { get; }
     string City { get; }