diff --git a/Iyzipay/Model/BasketItem.cs b/Iyzipay/Model/BasketItem.cs
index 1cbee4e..cb2256e 100644
--- a/Iyzipay/Model/BasketItem.cs
+++ b/Iyzipay/Model/BasketItem.cs
@@ -13,6 +13,7 @@ public class BasketItem : RequestStringConvertible
 		public String SubMerchantKey { get; set; }
 		public String SubMerchantPrice { get; set; }
 		public bool ChargedFromMerchant { get; set; }
+		public String WithholdingTax { get; set; }
 
 		public String ToPKIRequestString()
 		{
@@ -26,6 +27,7 @@ public String ToPKIRequestString()
 				.Append("subMerchantKey", SubMerchantKey)
 				.AppendPrice("subMerchantPrice", SubMerchantPrice)
 				.Append("chargedFromMerchant", ChargedFromMerchant)
+				.AppendPrice("withholdingTax", WithholdingTax)
 				.GetRequestString();
 		}
 	}
diff --git a/Iyzipay/Model/PaymentItem.cs b/Iyzipay/Model/PaymentItem.cs
index 979b62a..6525b3c 100644
--- a/Iyzipay/Model/PaymentItem.cs
+++ b/Iyzipay/Model/PaymentItem.cs
@@ -25,6 +25,7 @@ public class PaymentItem : IyzipayResourceV2
 		public string SubMerchantPayoutAmount { get; set; }
 		public string MerchantPayoutAmount { get; set; }
 		public ConvertedPayout ConvertedPayout { get; set; }
+		public string WithholdingTax { get; set; }
 
 		public static Task<PaymentItem> Update(UpdatePaymentItemRequest request, Options options)
 		{
diff --git a/Iyzipay/Request/UpdatePaymentItemRequest.cs b/Iyzipay/Request/UpdatePaymentItemRequest.cs
index 8c0e99e..093100b 100644
--- a/Iyzipay/Request/UpdatePaymentItemRequest.cs
+++ b/Iyzipay/Request/UpdatePaymentItemRequest.cs
@@ -7,6 +7,7 @@ public class UpdatePaymentItemRequest : BaseRequestV2
         public string SubMerchantKey { get; set; }
         public string PaymentTransactionId { get; set; }
         public string SubMerchantPrice { get; set; }
+        public string WithholdingTax { get; set; }
 
 
         public override string ToPKIRequestString()
@@ -16,6 +17,7 @@ public override string ToPKIRequestString()
                 .Append("subMerchantKey", SubMerchantKey)
                 .Append("paymentTransactionId", PaymentTransactionId)
                 .Append("subMerchantPrice", SubMerchantPrice)
+                .AppendPrice("withholdingTax", WithholdingTax)
                 .GetRequestString();
         }
     }