diff --git a/src/OT/glyf/VarCompositeGlyph.hh b/src/OT/glyf/VarCompositeGlyph.hh
index 5e778ef28..4e755a095 100644
--- a/src/OT/glyf/VarCompositeGlyph.hh
+++ b/src/OT/glyf/VarCompositeGlyph.hh
@@ -249,7 +249,7 @@ struct VarCompositeGlyphRecord
       unsigned axis_index = axis_width == 1 ? *p++ : *q++;
       signed v = axis_points[i].x;
       v = hb_clamp (v, -(1<<14), (1<<14));
-      setter[axis_index] = v;
+      setter[axis_index] += v;
     }
   }