diff --git a/xml/System.Collections.Immutable/ImmutableArray`1.xml b/xml/System.Collections.Immutable/ImmutableArray`1.xml
index f8aa8c6f96e..75dc739df0a 100644
--- a/xml/System.Collections.Immutable/ImmutableArray`1.xml
+++ b/xml/System.Collections.Immutable/ImmutableArray`1.xml
@@ -3688,7 +3688,7 @@ This member is an explicit interface member implementation. It can be used only
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- This is an O(1) operation and results in only a single (small) memory allocation. The mutable list that is returned is not thread-safe.  
+ This is an O(n) operation and copies all the elements of the immutable array into the Builder. The mutable list that is returned is not thread-safe.  
   
  ]]></format>
         </remarks>