diff --git a/piker/brokers/deribit/api.py b/piker/brokers/deribit/api.py
index b663d470..6f8f659d 100644
--- a/piker/brokers/deribit/api.py
+++ b/piker/brokers/deribit/api.py
@@ -270,7 +270,7 @@ class Client:
         json_rpc: Callable
 
     ) -> None:
-        self._pairs: dict[str, Any] = None
+        self._pairs: ChainMap[str, Pair] = ChainMap()
 
         config = get_config().get('option', {})