diff --git a/DynareBison.yy b/DynareBison.yy
index 343c859f..b2360f78 100644
--- a/DynareBison.yy
+++ b/DynareBison.yy
@@ -705,6 +705,7 @@ signed_float : PLUS FLOAT_NUMBER
                { $2->insert(0, "-"); $$ = $2; }
              | FLOAT_NUMBER
                { $$ = $1; }
+             | signed_integer
              ;
 
 estimated_params : ESTIMATED_PARAMS ';' estimated_list END { driver.estimated_params(); };