diff --git a/src/aeb_fate_maps.erl b/src/aeb_fate_maps.erl
index ed9e86a..c6b7b0b 100644
--- a/src/aeb_fate_maps.erl
+++ b/src/aeb_fate_maps.erl
@@ -134,7 +134,7 @@ write_cache(Key, Val, Map) ->
 
 %% -- Reference counting -----------------------------------------------------
 
--type refcount() :: #{id() => pos_integer()}.
+-type refcount() :: #{id() => integer()}.
 
 -spec refcount_zero() -> refcount().
 refcount_zero() -> #{}.