diff --git a/SVSim.Database/Services/Inventory/InventoryHistoryConfig.cs b/SVSim.Database/Services/Inventory/InventoryHistoryConfig.cs
new file mode 100644
index 0000000..f682d7d
--- /dev/null
+++ b/SVSim.Database/Services/Inventory/InventoryHistoryConfig.cs
@@ -0,0 +1,15 @@
+namespace SVSim.Database.Services.Inventory;
+
+/// <summary>
+/// Shared knobs for the viewer-acquire-history audit log. The write-side prune cap
+/// (in <c>InventoryTransaction</c>) and the read-side page size (in
+/// <c>ItemAcquireHistoryController</c>) both reference these constants so they cannot drift.
+/// </summary>
+public static class InventoryHistoryConfig
+{
+    /// <summary>
+    /// Maximum rows kept per viewer. Older rows are pruned by
+    /// <c>InventoryTransaction.CommitAsync</c>; the read endpoint pages exactly this many.
+    /// </summary>
+    public const int RetentionRowsPerViewer = 300;
+}
diff --git a/SVSim.Database/Services/Inventory/InventoryTransaction.cs b/SVSim.Database/Services/Inventory/InventoryTransaction.cs
index 2a99f75..610042a 100644
--- a/SVSim.Database/Services/Inventory/InventoryTransaction.cs
+++ b/SVSim.Database/Services/Inventory/InventoryTransaction.cs
@@ -9,7 +9,7 @@ namespace SVSim.Database.Services.Inventory;
 
 internal sealed class InventoryTransaction : IInventoryTransaction
 {
-    private const int AcquireHistoryRetention = 300;
+    private const int AcquireHistoryRetention = InventoryHistoryConfig.RetentionRowsPerViewer;
 
     private readonly SVSimDbContext _db;
     private readonly IDbContextTransaction _dbTx;
diff --git a/SVSim.EmulatedEntrypoint/Controllers/ItemAcquireHistoryController.cs b/SVSim.EmulatedEntrypoint/Controllers/ItemAcquireHistoryController.cs
index 55728f4..ba5a35f 100644
--- a/SVSim.EmulatedEntrypoint/Controllers/ItemAcquireHistoryController.cs
+++ b/SVSim.EmulatedEntrypoint/Controllers/ItemAcquireHistoryController.cs
@@ -1,6 +1,8 @@
+using System.Globalization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
 using SVSim.Database;
+using SVSim.Database.Services.Inventory;
 using SVSim.EmulatedEntrypoint.Models.Dtos.ItemAcquireHistory;
 
 namespace SVSim.EmulatedEntrypoint.Controllers;
@@ -9,7 +11,6 @@ namespace SVSim.EmulatedEntrypoint.Controllers;
 public sealed class ItemAcquireHistoryController : SVSimController
 {
     private const string WireDateFormat = "yyyy-MM-dd HH:mm:ss";
-    private const int PageSize = 300;
 
     private readonly SVSimDbContext _db;
 
@@ -26,7 +27,7 @@ public sealed class ItemAcquireHistoryController : SVSimController
             .Where(h => h.ViewerId == viewerId)
             .OrderByDescending(h => h.AcquireTime)
             .ThenByDescending(h => h.Id)
-            .Take(PageSize)
+            .Take(InventoryHistoryConfig.RetentionRowsPerViewer)
             .AsNoTracking()
             .ToListAsync(ct);
 
@@ -38,7 +39,7 @@ public sealed class ItemAcquireHistoryController : SVSimController
                 RewardDetailId = h.RewardDetailId.ToString(),
                 RewardCount = h.RewardCount.ToString(),
                 AcquireType = h.AcquireType.ToString(),
-                AcquireTime = h.AcquireTime.ToString(WireDateFormat),
+                AcquireTime = h.AcquireTime.ToString(WireDateFormat, CultureInfo.InvariantCulture),
                 Message = h.Message,
             }).ToList(),
         };