diff --git a/src/System.Management.Automation/engine/regex.cs b/src/System.Management.Automation/engine/regex.cs
index f4e7ee1ecd6..17d729c52ea 100644
--- a/src/System.Management.Automation/engine/regex.cs
+++ b/src/System.Management.Automation/engine/regex.cs
@@ -53,6 +53,10 @@ public sealed class WildcardPattern
         // char that escapes special chars
         private const char escapeChar = '`';
 
+        // Threshold for stack allocation.
+        // The size is less than MaxShortPath = 260.
+        private const int StackAllocThreshold = 256;
+
         // we convert a wildcard pattern to a predicate
         private Predicate<string> _isMatch;
 
@@ -203,15 +207,20 @@ internal static string Escape(string pattern, char[] charsNotToEscape)
         {
             if (pattern == null)
             {
-                throw PSTraceSource.NewArgumentNullException("pattern");
+                throw PSTraceSource.NewArgumentNullException(nameof(pattern));
             }
 
             if (charsNotToEscape == null)
             {
-                throw PSTraceSource.NewArgumentNullException("charsNotToEscape");
+                throw PSTraceSource.NewArgumentNullException(nameof(charsNotToEscape));
+            }
+
+            if (pattern == string.Empty)
+            {
+                return pattern;
             }
 
-            char[] temp = new char[pattern.Length * 2 + 1];
+            Span<char> temp = pattern.Length < StackAllocThreshold ? stackalloc char[pattern.Length * 2 + 1] : new char[pattern.Length * 2 + 1];
             int tempIndex = 0;
 
             for (int i = 0; i < pattern.Length; i++)
@@ -231,13 +240,13 @@ internal static string Escape(string pattern, char[] charsNotToEscape)
 
             string s = null;
 
-            if (tempIndex > 0)
+            if (tempIndex == pattern.Length)
             {
-                s = new string(temp, 0, tempIndex);
+                s = pattern;
             }
             else
             {
-                s = string.Empty;
+                s = new string(temp.Slice(0, tempIndex));
             }
 
             return s;
@@ -312,10 +321,16 @@ public static string Unescape(string pattern)
         {
             if (pattern == null)
             {
-                throw PSTraceSource.NewArgumentNullException("pattern");
+                throw PSTraceSource.NewArgumentNullException(nameof(pattern));
             }
 
-            char[] temp = new char[pattern.Length];
+            if (pattern == string.Empty)
+            {
+                return pattern;
+            }
+
+            Span<char> temp = pattern.Length < StackAllocThreshold ? stackalloc char[pattern.Length] : new char[pattern.Length];
+
             int tempIndex = 0;
             bool prevCharWasEscapeChar = false;
 
@@ -361,13 +376,13 @@ public static string Unescape(string pattern)
 
             string s = null;
 
-            if (tempIndex > 0)
+            if (tempIndex == pattern.Length)
             {
-                s = new string(temp, 0, tempIndex);
+                s = pattern;
             }
             else
             {
-                s = string.Empty;
+                s = new string(temp.Slice(0, tempIndex));
             }
 
             return s;