diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/IncludedDataEnum.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/IncludedDataEnum.cs
index 3f7aad95..2c32652d 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/IncludedDataEnum.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/IncludedDataEnum.cs
@@ -62,6 +62,17 @@ public enum IncludedDataEnum
         [EnumMember(Value = "PACKAGES")]
         PACKAGES = 8,
 
+        /// <summary>
+        /// Information about tax
+        /// </summary>
+        [EnumMember(Value = "TAX")]
+        TAX = 9,
+
+        /// <summary>
+        /// Information about payment
+        /// </summary>
+        [EnumMember(Value = "PAYMENT")]
+        PAYMENT = 10,
     }
 
 }
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItem.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItem.cs
index 528304c2..667d0b5c 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItem.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItem.cs
@@ -35,6 +35,7 @@ protected OrderItem() { }
         /// <param name="promotion">Details about any discounts, coupons, or promotional offers applied to this item.</param>
         /// <param name="cancellation">The cancellation information of the order item.</param>
         /// <param name="fulfillment">Information about how the order item should be processed, packed, and shipped to the customer.</param>
+        /// <param name="tax">Tax information associated with this specific order item.</param>
         public OrderItem(string orderItemId,
                          int quantityOrdered,
                          Measurement measurement,
@@ -44,7 +45,8 @@ public OrderItem(string orderItemId,
                          Expense expense,
                          Promotion promotion,
                          Cancellation cancellation,
-                         OrderItemFulfillment fulfillment)
+                         OrderItemFulfillment fulfillment,
+                         OrderItemTax tax)
         {
             this.OrderItemId = orderItemId;
             this.QuantityOrdered = quantityOrdered;
@@ -56,6 +58,7 @@ public OrderItem(string orderItemId,
             this.Promotion = promotion;
             this.Cancellation = cancellation;
             this.Fulfillment = fulfillment;
+            this.Tax = tax;
         }
 
         /// <summary>
@@ -128,6 +131,14 @@ public OrderItem(string orderItemId,
         [DataMember(Name = "fulfillment", EmitDefaultValue = false)]
         public OrderItemFulfillment Fulfillment { get; set; }
 
+        /// <summary>
+        /// Tax information associated with this specific order item,
+        /// including the responsible party and the tax collection model.
+        /// </summary>
+        /// <value>Tax information associated with this specific order item.</value>
+        [DataMember(Name = "tax", EmitDefaultValue = false)]
+        public OrderItemTax Tax { get; set; }
+
 
         /// <summary>
         /// Returns the string presentation of the object
@@ -147,6 +158,7 @@ public override string ToString()
             sb.Append("  Promotion: ").Append(Promotion).Append("\n");
             sb.Append("  Cancellation: ").Append(Cancellation).Append("\n");
             sb.Append("  Fulfillment: ").Append(Fulfillment).Append("\n");
+            sb.Append("  Tax: ").Append(Tax).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
         }
@@ -230,6 +242,11 @@ public bool Equals(OrderItem input)
                     this.Fulfillment == input.Fulfillment ||
                     (this.Fulfillment != null &&
                     this.Fulfillment.Equals(input.Fulfillment))
+                ) &&
+                (
+                    this.Tax == input.Tax ||
+                    (this.Tax != null &&
+                    this.Tax.Equals(input.Tax))
                 );
         }
 
@@ -262,6 +279,8 @@ public override int GetHashCode()
                     hashCode = hashCode * 59 + this.Cancellation.GetHashCode();
                 if (this.Fulfillment != null)
                     hashCode = hashCode * 59 + this.Fulfillment.GetHashCode();
+                if (this.Tax != null)
+                    hashCode = hashCode * 59 + this.Tax.GetHashCode();
                 return hashCode;
             }
         }
@@ -277,4 +296,4 @@ public override int GetHashCode()
         }
     }
 
-}
+}
\ No newline at end of file
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTax.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTax.cs
new file mode 100644
index 00000000..87569f0d
--- /dev/null
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTax.cs
@@ -0,0 +1,113 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Runtime.Serialization;
+using System.Text;
+
+namespace FikaAmazonAPI.AmazonSpApiSDK.Models.OrdersV20260101
+{
+    /// <summary>
+    /// Represents tax information for an order item, containing a list of tax collections.
+    /// </summary>
+    [DataContract]
+    public partial class OrderItemTax : IEquatable<OrderItemTax>, IValidatableObject
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="OrderItemTax"/> class.
+        /// </summary>
+        public OrderItemTax()
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="OrderItemTax"/> class.
+        /// </summary>
+        /// <param name="orderItemTaxCollections">A list of tax collections associated with this order item.</param>
+        public OrderItemTax(List<OrderItemTaxCollection> orderItemTaxCollections)
+        {
+            this.TaxCollection = orderItemTaxCollections;
+        }
+
+        /// <summary>
+        /// A list of tax collections for this order item.
+        /// Each entry contains details about the responsible party and the tax model (e.g. MARKETPLACE_FACILITATOR).
+        /// </summary>
+        [DataMember(Name = "taxCollections", EmitDefaultValue = false)]
+        public List<OrderItemTaxCollection> TaxCollection { get; set; }
+
+        /// <summary>
+        /// Returns the string representation of the object.
+        /// </summary>
+        /// <returns>String representation of the object</returns>
+        public override string ToString()
+        {
+            var sb = new StringBuilder();
+            sb.Append("class OrderItemTax {\n");
+            sb.Append("  TaxCollection: ").Append(TaxCollection).Append("\n");
+            sb.Append("}\n");
+            return sb.ToString();
+        }
+
+        /// <summary>
+        /// Returns the JSON string representation of the object.
+        /// </summary>
+        /// <returns>JSON string representation of the object</returns>
+        public virtual string ToJson()
+        {
+            return JsonConvert.SerializeObject(this, Formatting.Indented);
+        }
+
+        /// <summary>
+        /// Returns true if the given object is equal to this instance.
+        /// </summary>
+        /// <param name="obj">Object to be compared</param>
+        /// <returns>Boolean</returns>
+        public override bool Equals(object obj)
+        {
+            return this.Equals(obj as OrderItemTax);
+        }
+
+        /// <summary>
+        /// Returns true if the given <see cref="OrderItemTax"/> instance is equal to this instance.
+        /// </summary>
+        /// <param name="input">Instance of <see cref="OrderItemTax"/> to be compared</param>
+        /// <returns>Boolean</returns>
+        public bool Equals(OrderItemTax input)
+        {
+            if (input == null)
+                return false;
+
+            return
+                this.TaxCollection == input.TaxCollection ||
+                (this.TaxCollection != null &&
+                 this.TaxCollection.SequenceEqual(input.TaxCollection));
+        }
+
+        /// <summary>
+        /// Returns the hash code for this instance.
+        /// </summary>
+        /// <returns>Hash code</returns>
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                int hashCode = 41;
+                if (this.TaxCollection != null)
+                    hashCode = hashCode * 59 + this.TaxCollection.GetHashCode();
+                return hashCode;
+            }
+        }
+
+        /// <summary>
+        /// Validates all properties of the instance.
+        /// </summary>
+        /// <param name="validationContext">Validation context</param>
+        /// <returns>Validation results</returns>
+        IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> IValidatableObject.Validate(ValidationContext validationContext)
+        {
+            yield break;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTaxCollection.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTaxCollection.cs
new file mode 100644
index 00000000..1e8312df
--- /dev/null
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTaxCollection.cs
@@ -0,0 +1,128 @@
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Runtime.Serialization;
+using System.Text;
+
+namespace FikaAmazonAPI.AmazonSpApiSDK.Models.OrdersV20260101
+{
+    /// <summary>
+    /// Represents a single tax collection entry for an order item,
+    /// containing the responsible party and the applied tax model.
+    /// </summary>
+    [DataContract]
+    public partial class OrderItemTaxCollection : IEquatable<OrderItemTaxCollection>, IValidatableObject
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="OrderItemTaxCollection"/> class.
+        /// </summary>
+        public OrderItemTaxCollection()
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="OrderItemTaxCollection"/> class.
+        /// </summary>
+        /// <param name="responsibleParty">The party responsible for collecting the tax (e.g. "Amazon EU S.a.r.L.").</param>
+        /// <param name="model">The tax collection model applied to this order item.</param>
+        public OrderItemTaxCollection(string responsibleParty, OrderItemTaxCollectionEnum? model = null)
+        {
+            this.ResponsibleParty = responsibleParty;
+            this.Model = model;
+        }
+
+        /// <summary>
+        /// The party responsible for collecting the tax for this order item (e.g. "Amazon EU S.a.r.L.").
+        /// </summary>
+        [DataMember(Name = "responsibleParty", EmitDefaultValue = false)]
+        public string ResponsibleParty { get; set; }
+
+        /// <summary>
+        /// The tax collection model applied to this order item.
+        /// </summary>
+        [DataMember(Name = "model", EmitDefaultValue = false)]
+        public OrderItemTaxCollectionEnum? Model { get; set; }
+
+        /// <summary>
+        /// Returns the string representation of the object.
+        /// </summary>
+        /// <returns>String representation of the object</returns>
+        public override string ToString()
+        {
+            var sb = new StringBuilder();
+            sb.Append("class OrderItemTaxCollection {\n");
+            sb.Append("  ResponsibleParty: ").Append(ResponsibleParty).Append("\n");
+            sb.Append("  Model: ").Append(Model).Append("\n");
+            sb.Append("}\n");
+            return sb.ToString();
+        }
+
+        /// <summary>
+        /// Returns the JSON string representation of the object.
+        /// </summary>
+        /// <returns>JSON string representation of the object</returns>
+        public virtual string ToJson()
+        {
+            return JsonConvert.SerializeObject(this, Formatting.Indented);
+        }
+
+        /// <summary>
+        /// Returns true if the given object is equal to this instance.
+        /// </summary>
+        /// <param name="obj">Object to be compared</param>
+        /// <returns>Boolean</returns>
+        public override bool Equals(object obj)
+        {
+            return this.Equals(obj as OrderItemTaxCollection);
+        }
+
+        /// <summary>
+        /// Returns true if the given <see cref="OrderItemTaxCollection"/> instance is equal to this instance.
+        /// </summary>
+        /// <param name="input">Instance of <see cref="OrderItemTaxCollection"/> to be compared</param>
+        /// <returns>Boolean</returns>
+        public bool Equals(OrderItemTaxCollection input)
+        {
+            if (input == null)
+                return false;
+
+            return
+                (
+                    this.ResponsibleParty == input.ResponsibleParty ||
+                    (this.ResponsibleParty != null &&
+                     this.ResponsibleParty.Equals(input.ResponsibleParty))
+                ) &&
+                (
+                    this.Model == input.Model
+                );
+        }
+
+        /// <summary>
+        /// Returns the hash code for this instance.
+        /// </summary>
+        /// <returns>Hash code</returns>
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                int hashCode = 41;
+                if (this.ResponsibleParty != null)
+                    hashCode = hashCode * 59 + this.ResponsibleParty.GetHashCode();
+                hashCode = hashCode * 59 + this.Model.GetHashCode();
+                return hashCode;
+            }
+        }
+
+        /// <summary>
+        /// Validates all properties of the instance.
+        /// </summary>
+        /// <param name="validationContext">Validation context</param>
+        /// <returns>Validation results</returns>
+        IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> IValidatableObject.Validate(ValidationContext validationContext)
+        {
+            yield break;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTaxCollectionEnum.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTaxCollectionEnum.cs
new file mode 100644
index 00000000..5b12a044
--- /dev/null
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/OrderItemTaxCollectionEnum.cs
@@ -0,0 +1,22 @@
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+using System;
+using System.Collections.Generic;
+using System.Runtime.Serialization;
+using System.Text;
+
+namespace FikaAmazonAPI.AmazonSpApiSDK.Models.OrdersV20260101
+{
+    /// <summary>
+    /// Specifies the tax collection model applied to this order item.
+    /// </summary>
+    [JsonConverter(typeof(StringEnumConverter))]
+    public enum OrderItemTaxCollectionEnum
+    {
+        /// <summary>
+        /// Tax is collected by the marketplace facilitator.
+        /// </summary>
+        [EnumMember(Value = "MARKETPLACE_FACILITATOR")]
+        MARKETPLACE_FACILITATOR = 1
+    }
+}
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/PriceDesignationEnum.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/PriceDesignationEnum.cs
index 0fe7071c..06e1f5dc 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/PriceDesignationEnum.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/PriceDesignationEnum.cs
@@ -1,9 +1,7 @@
 using Newtonsoft.Json;
 using Newtonsoft.Json.Converters;
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
-using System.Text;
+
 
 namespace FikaAmazonAPI.AmazonSpApiSDK.Models.OrdersV20260101
 {
@@ -19,6 +17,12 @@ public enum PriceDesignationEnum
         /// </summary>
         [EnumMember(Value = "BUSINESS_PRICE")]
         BUSINESS_PRICE = 1,
+
+        /// <summary>
+        /// Enum value for type QUANTITY_PRICE
+        /// </summary>
+        [EnumMember(Value = "QUANTITY_PRICE")]
+        QUANTITY_PRICE = 2
     }
 
 }
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/ProgramEnum.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/ProgramEnum.cs
index 052ceced..dfa199d1 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/ProgramEnum.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/OrdersV20260101/ProgramEnum.cs
@@ -73,6 +73,12 @@ public enum ProgramEnum
         /// </summary>
         [EnumMember(Value = "PRIME")]
         PRIME = 10,
+
+        /// <summary>
+        /// Enum value for type INVOICE_BY_AMAZON
+        /// </summary>
+        [EnumMember(Value = "INVOICE_BY_AMAZON")]
+        INVOICE_BY_AMAZON = 11
     }
 
 }