diff --git a/preprocessor/DynareBison.yy b/preprocessor/DynareBison.yy
index b5f8e3e831657975f9e5b247840c592122a3748c..5b1fd7f80d6272b598b3f24b92830aac28f6949d 100644
--- a/preprocessor/DynareBison.yy
+++ b/preprocessor/DynareBison.yy
@@ -713,6 +713,7 @@ signed_float : PLUS FLOAT_NUMBER
                { $2->insert(0, "-"); $$ = $2; }
              | FLOAT_NUMBER
                { $$ = $1; }
+             | signed_integer
              ;
 
 estimated_params : ESTIMATED_PARAMS ';' estimated_list END { driver.estimated_params(); };