diff --git a/src/bnhtrade.Core/Logic/Validate/Format.cs b/src/bnhtrade.Core/Logic/Validate/Format.cs
index 989b485..0fc5a90 100644
--- a/src/bnhtrade.Core/Logic/Validate/Format.cs
+++ b/src/bnhtrade.Core/Logic/Validate/Format.cs
@@ -45,6 +45,20 @@ namespace bnhtrade.Core.Logic.Validate
             return true;
         }
 
+        /// <summary>
+        /// Validates that a stock number string is in the format 'STK#000000' (six digits).
+        /// </summary>
+        /// <param name="stockNumber"></param>
+        /// <returns></returns>
+        public static bool StockNumber(string stockNumber)
+        {
+            if (string.IsNullOrEmpty(stockNumber))
+                return false;
+
+            // Check for exact match: STK# followed by 6 digits
+            return System.Text.RegularExpressions.Regex.IsMatch(stockNumber, @"^STK#\d{6}$");
+        }
+
         /// <summary>
         /// Checks the datetime is not default and is utc
         /// </summary>
diff --git a/src/bnhtrade.Core/Model/Stock/StockJournal.cs b/src/bnhtrade.Core/Model/Stock/StockJournal.cs
index 8627a67..d64ce43 100644
--- a/src/bnhtrade.Core/Model/Stock/StockJournal.cs
+++ b/src/bnhtrade.Core/Model/Stock/StockJournal.cs
@@ -1,4 +1,7 @@
-using System;
+using bnhtrade.Core.Logic.Validate;
+using bnhtrade.Core.Model.Account;
+using FikaAmazonAPI.AmazonSpApiSDK.Models.FulfillmentInboundv20240320;
+using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.Linq;
@@ -9,7 +12,7 @@ namespace bnhtrade.Core.Model.Stock
 {
     public class StockJournal : IValidatableObject
     {
-        public StockJournal(int stockJournalId, StockJournalType stockJournalType, int stockId, int stockNumber, DateTime entryDate, DateTime postDate, DateTime lastModified, bool isLocked, List<JournalPost> journalPosts)
+        public StockJournal(int stockJournalId, StockJournalType stockJournalType, int stockId, string stockNumber, DateTime entryDate, DateTime postDate, DateTime lastModified, bool isLocked, List<StockJournalPost> journalPosts)
         {
             StockJournalId = stockJournalId;
             StockJournalType = stockJournalType;
@@ -19,16 +22,21 @@ namespace bnhtrade.Core.Model.Stock
             PostDate = postDate;
             LastModified = lastModified;
             IsLocked = isLocked;
-            JournalPosts = journalPosts ?? throw new ArgumentNullException(nameof(journalPosts), "Journal posts cannot be null.");
+            StockJournalPosts = journalPosts ?? throw new ArgumentNullException(nameof(journalPosts), "Journal posts cannot be null.");
         }
 
+        [Required()]
+        [Range(1, int.MaxValue, ErrorMessage = "StockJournalId must be greater than 0.")]
         public int StockJournalId { get; }
 
         public StockJournalType StockJournalType { get; }
 
+        [Required()]
+        [Range(1, int.MaxValue, ErrorMessage = "StockId must be greater than 0.")]
         public int StockId { get; }
 
-        public int StockNumber { get; }
+        [Required(ErrorMessage = "Stock number is required.")]
+        public string StockNumber { get; }
 
         public DateTime EntryDate { get; }
 
@@ -38,18 +46,17 @@ namespace bnhtrade.Core.Model.Stock
 
         public bool IsLocked { get; }
 
-        public List<JournalPost> JournalPosts { get; }
+        public List<StockJournalPost> StockJournalPosts { get; }
 
-        public class JournalPost
+        public class StockJournalPost : IValidatableObject
         {
-            public JournalPost(int journalPostId, Status status, int quantity)
+            public StockJournalPost(int journalPostId, Status status, int quantity)
             {
-                JournalPostId = journalPostId;
+                StockJournalPostId = journalPostId;
                 Status = status;
                 Quantity = quantity;
             }
-
-            public int JournalPostId { get; }
+            public int StockJournalPostId { get; }
 
             [Required()]
             public Status Status { get; }
@@ -94,12 +101,64 @@ namespace bnhtrade.Core.Model.Stock
                     }
                 }
             }
+
+            public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+            {
+                var validationResults = new List<ValidationResult>();
+
+                if (Quantity == 0)
+                {
+                    validationResults.Add(new ValidationResult("Quantity cannot be zero for a journal post.", new[] { nameof(Quantity) }));
+                }
+
+                return validationResults;
+            }
         }
 
         public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
         {
-            throw new NotImplementedException();
-        }
+            var validationResults = new List<ValidationResult>();
 
+            // dates are in UTC format
+            if (EntryDate.Kind != DateTimeKind.Utc || EntryDate == default(DateTime))
+            {
+                validationResults.Add(new ValidationResult("Entry Date must be in UTC format and not a default value.", new[] { nameof(EntryDate) }));
+            }
+            if (PostDate.Kind != DateTimeKind.Utc || PostDate == default(DateTime))
+            {
+                validationResults.Add(new ValidationResult("PostDate must be in UTC format and not a default value.", new[] { nameof(PostDate) }));
+            }
+            if (LastModified.Kind != DateTimeKind.Utc || LastModified == default(DateTime))
+            {
+                validationResults.Add(new ValidationResult("LastModified must be in UTC format and not a default value.", new[] { nameof(LastModified) }));
+            }
+
+            if (Format.StockNumber(StockNumber) == false)
+            {
+                validationResults.Add(new ValidationResult("StockNumber must be in the format 'STK#000000'.", new[] { nameof(StockNumber) }));
+            }
+
+            // Validate each StockJournalPost using its own context and Validate method
+            int sum = 0;
+            for (int i = 0; i < StockJournalPosts.Count; i++)
+            {
+                sum += StockJournalPosts[i].Quantity;
+
+                var post = StockJournalPosts[i];
+                var postContext = new ValidationContext(post, validationContext, validationContext.Items);
+                foreach (var result in post.Validate(postContext))
+                {
+                    // Prefix property name with the index for clarity
+                    var memberNames = result.MemberNames.Select(name => $"StockJournalPosts[{i}].{name}");
+                    validationResults.Add(new ValidationResult(result.ErrorMessage, memberNames));
+                }
+            }
+            if (sum != 0)
+            {
+                validationResults.Add(new ValidationResult("The sum of all journal posts must equal zero.", new[] { nameof(StockJournalPosts) }));
+            }
+
+            return validationResults;
+        }
     }
 }