diff --git a/src/System.Management.Automation/CoreCLR/CorePsPlatform.cs b/src/System.Management.Automation/CoreCLR/CorePsPlatform.cs
index 859aa8ecfe..dd0877710d 100644
--- a/src/System.Management.Automation/CoreCLR/CorePsPlatform.cs
+++ b/src/System.Management.Automation/CoreCLR/CorePsPlatform.cs
@@ -184,7 +184,7 @@ namespace System.Management.Automation
 #endif
 
         // format files
-        internal static readonly List<string> FormatFileNames = new()
+        internal static readonly string[] FormatFileNames = new string[]
         {
             "Certificate.format.ps1xml",
             "Diagnostics.format.ps1xml",
diff --git a/src/System.Management.Automation/engine/InitialSessionState.cs b/src/System.Management.Automation/engine/InitialSessionState.cs
index 815f7ea562..05eb871053 100644
--- a/src/System.Management.Automation/engine/InitialSessionState.cs
+++ b/src/System.Management.Automation/engine/InitialSessionState.cs
@@ -1434,9 +1434,6 @@ namespace System.Management.Automation.Runspaces
             return iss;
         }
 
-        // Porting note: moved to Platform so we have one list to maintain
-        private static readonly string[] s_PSCoreFormatFileNames = Platform.FormatFileNames.ToArray();
-
         private static void IncludePowerShellCoreFormats(InitialSessionState iss)
         {
             string psHome = Utils.DefaultPowerShellAppBase;
@@ -1446,7 +1443,7 @@ namespace System.Management.Automation.Runspaces
             }
 
             iss.Formats.Clear();
-            foreach (var coreFormat in s_PSCoreFormatFileNames)
+            foreach (var coreFormat in Platform.FormatFileNames)
             {
                 iss.Formats.Add(new SessionStateFormatEntry(Path.Combine(psHome, coreFormat)));
             }