diff --git a/exist-core/src/main/java/org/exist/xquery/functions/fn/FnFormatNumbers.java b/exist-core/src/main/java/org/exist/xquery/functions/fn/FnFormatNumbers.java
index 1a945eb026c..3633d2c71fc 100644
--- a/exist-core/src/main/java/org/exist/xquery/functions/fn/FnFormatNumbers.java
+++ b/exist-core/src/main/java/org/exist/xquery/functions/fn/FnFormatNumbers.java
@@ -714,9 +714,6 @@ private String format(final NumericValue number, final DecimalFormat decimalForm
         final int minimumExponentSize = subPicture.getMinimumExponentSize();
         if (minimumExponentSize > 0) {
             formatted.append(decimalFormat.exponentSeparator);
-            if (exp < 0) {
-                formatted.append(decimalFormat.minusSign);
-            }
 
             final CodePointString expStr = new CodePointString(String.valueOf(exp));
 
diff --git a/exist-core/src/test/xquery/numbers/format-numbers.xql b/exist-core/src/test/xquery/numbers/format-numbers.xql
index 68a83792d3a..23080940618 100644
--- a/exist-core/src/test/xquery/numbers/format-numbers.xql
+++ b/exist-core/src/test/xquery/numbers/format-numbers.xql
@@ -303,4 +303,17 @@ declare
     %test:assertEquals("0.0")
 function fd:decimal-zeros($picture as xs:string) {
     format-number(0, $picture)
+};
+
+declare
+    %test:args(1.234567E10,"0.000e0")
+    %test:assertEquals("1.235e10")
+    %test:args(1.234567E-10,"0.000e0")
+    %test:assertEquals("1.235e-10")
+    %test:args(0.000000000123456,"0.000e0")
+    %test:assertEquals("1.235e-10")
+    %test:args(1.234567e-10,"0.000e0")
+    %test:assertEquals("1.235e-10")
+function fd:exponent-fails($number as xs:double, $picture as xs:string) {
+    format-number($number, $picture)
 };
\ No newline at end of file