diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index dbead7c8..86435616 100644
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -1046,11 +1046,14 @@ SEXP_API sexp sexp_make_unsigned_integer(sexp ctx, sexp_luint_t x);
 #define sexp_negativep(x) (sexp_exact_negativep(x) ||                   \
                            (sexp_flonump(x) && sexp_flonum_value(x) < 0))
 #define sexp_positivep(x) (!(sexp_negativep(x)))
-#define sexp_pedantic_negativep(x) (sexp_exact_negativep(x) ||          \
-                                    (sexp_flonump(x) &&                 \
-                                     ((sexp_flonum_value(x) < 0) ||     \
-                                      (sexp_flonum_value(x) == 0 && \
-                                       1.0 / sexp_flonum_value(x) < 0))))
+#define sexp_pedantic_negativep(x) (                 \
+  sexp_exact_negativep(x) ||                         \
+  (sexp_ratiop(x) &&                                 \
+   sexp_exact_negativep(sexp_ratio_numerator(x))) || \
+  (sexp_flonump(x) &&                                \
+   ((sexp_flonum_value(x) < 0) ||                    \
+    (sexp_flonum_value(x) == 0 &&                    \
+     1.0 / sexp_flonum_value(x) < 0))))
 
 #if SEXP_USE_BIGNUMS
 #define sexp_oddp(x) (sexp_fixnump(x) ? sexp_unbox_fixnum(x) & 1 : \