diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,7 +1,10 @@
+texmath (0.8.6.5)
+
+  * Fixed transposition of sub/super on operators (jgm/pandoc#3040).
+
 texmath (0.8.6.4)
 
-  * Handle equation environment (without numbering).  This is similar
-    to the way we handle environments like align.
+  * Support 'equation' environment, without the numbering of course.
 
 texmath (0.8.6.3)
 
diff --git a/src/Text/TeXMath/Writers/OMML.hs b/src/Text/TeXMath/Writers/OMML.hs
--- a/src/Text/TeXMath/Writers/OMML.hs
+++ b/src/Text/TeXMath/Writers/OMML.hs
@@ -117,11 +117,11 @@
   case exp' of
        EOver convertible x y
          | isNary x  ->
-             EGrouped [EUnderover convertible x y emptyGroup, next] : rest
+             EGrouped [EUnderover convertible x emptyGroup y, next] : rest
          | convertible && dt == DisplayInline -> ESuper x y : xs
        EUnder convertible x y
          | isNary x  ->
-             EGrouped [EUnderover convertible x emptyGroup y, next] : rest
+             EGrouped [EUnderover convertible x y emptyGroup, next] : rest
          | convertible && dt == DisplayInline -> ESub x y : xs
        EUnderover convertible x y z
          | isNary x  ->
diff --git a/tests/writers/sphere_volume.omml b/tests/writers/sphere_volume.omml
--- a/tests/writers/sphere_volume.omml
+++ b/tests/writers/sphere_volume.omml
@@ -142,15 +142,15 @@
             <m:naryPr>
               <m:chr m:val="∭" />
               <m:limLoc m:val="undOvr" />
-              <m:subHide m:val="1" />
-              <m:supHide m:val="0" />
+              <m:subHide m:val="0" />
+              <m:supHide m:val="1" />
             </m:naryPr>
-            <m:sub />
-            <m:sup>
+            <m:sub>
               <m:r>
                 <m:t>S</m:t>
               </m:r>
-            </m:sup>
+            </m:sub>
+            <m:sup />
             <m:e />
           </m:nary>
           <m:sSup>
diff --git a/tests/writers/substack.omml b/tests/writers/substack.omml
--- a/tests/writers/substack.omml
+++ b/tests/writers/substack.omml
@@ -8,11 +8,10 @@
       <m:naryPr>
         <m:chr m:val="∑" />
         <m:limLoc m:val="undOvr" />
-        <m:subHide m:val="1" />
-        <m:supHide m:val="0" />
+        <m:subHide m:val="0" />
+        <m:supHide m:val="1" />
       </m:naryPr>
-      <m:sub />
-      <m:sup>
+      <m:sub>
         <m:m>
           <m:mPr>
             <m:baseJc m:val="center" />
@@ -65,7 +64,8 @@
             </m:e>
           </m:mr>
         </m:m>
-      </m:sup>
+      </m:sub>
+      <m:sup />
       <m:e>
         <m:r>
           <m:t>P</m:t>
diff --git a/texmath.cabal b/texmath.cabal
--- a/texmath.cabal
+++ b/texmath.cabal
@@ -1,5 +1,5 @@
 Name:                texmath
-Version:             0.8.6.4
+Version:             0.8.6.5
 Cabal-Version:       >= 1.10
 Build-type:          Simple
 Synopsis:            Conversion between formats used to represent mathematics.