diff --git a/packages/loot-core/src/server/importers/ynab5-types.d.ts b/packages/loot-core/src/server/importers/ynab5-types.d.ts
index f860a7a41d9..45a63c44bd1 100644
--- a/packages/loot-core/src/server/importers/ynab5-types.d.ts
+++ b/packages/loot-core/src/server/importers/ynab5-types.d.ts
@@ -25,7 +25,7 @@ export namespace YNAB5 {
     id: string;
     name: string;
     deleted: boolean;
-    transfer_acct: string | null
+    transfer_acct?: string
   }
 
   interface CategoryGroup {