diff --git a/exchange_calendars/calendar_utils.py b/exchange_calendars/calendar_utils.py
index 4cbc8432..c9c40b5e 100644
--- a/exchange_calendars/calendar_utils.py
+++ b/exchange_calendars/calendar_utils.py
@@ -127,6 +127,9 @@
     "NASDAQ": "XNYS",
     "BATS": "XNYS",
     "XNAS": "XNYS",
+    "ARCX": "XNYS",
+    "OOTC": "XNYS",
+    "XTSX": "XTSE",
     "FWB": "XFRA",
     "LSE": "XLON",
     "TSX": "XTSE",