diff --git a/src/abacus-ts/ontology.ts b/src/abacus-ts/ontology.ts
index 817723c1a..9c5bf86cf 100644
--- a/src/abacus-ts/ontology.ts
+++ b/src/abacus-ts/ontology.ts
@@ -192,7 +192,7 @@ interface BonsaiHelpersShape {
   markets: {
     createSelectMarketSummaryById: ParameterizedSelector<
       PerpetualMarketSummary | undefined,
-      [string]
+      [string | undefined]
     >;
   };
   forms: {