diff --git a/src/java/org/apache/poi/ss/usermodel/DataFormatter.java b/src/java/org/apache/poi/ss/usermodel/DataFormatter.java
index 7bd3eaad8..6f0d830d3 100644
--- a/src/java/org/apache/poi/ss/usermodel/DataFormatter.java
+++ b/src/java/org/apache/poi/ss/usermodel/DataFormatter.java
@@ -344,6 +344,7 @@ public class DataFormatter implements Observer {
         
         // Build a formatter, and cache it
         format = createFormat(cellValue, formatIndex, formatStr);
+        formats.put(formatStr, format);
         return format;
     }