diff --git a/src/interface/builder.rs b/src/interface/builder.rs
index 72136af7..ee888898 100644
--- a/src/interface/builder.rs
+++ b/src/interface/builder.rs
@@ -359,7 +359,7 @@ pub struct OperationBuilder<Seal: ExposedSeal> {
     global: GlobalState,
     // rights: TinyOrdMap<AssignmentType, Confined<HashSet<BuilderSeal<Seal>>, 1, U8>>,
     fungible:
-        TinyOrdMap<AssignmentType, Confined<HashMap<BuilderSeal<Seal>, RevealedValue>, 1, U8>>,
+        TinyOrdMap<AssignmentType, Confined<HashMap<BuilderSeal<Seal>, RevealedValue>, 1, U16>>,
     data: TinyOrdMap<AssignmentType, Confined<HashMap<BuilderSeal<Seal>, RevealedData>, 1, U8>>,
     // TODO: add attachments
     // TODO: add valencies