diff --git a/message_ix_models/tools/costs/decay.py b/message_ix_models/tools/costs/decay.py
index a28fcb034..8917b6434 100644
--- a/message_ix_models/tools/costs/decay.py
+++ b/message_ix_models/tools/costs/decay.py
@@ -11,7 +11,7 @@
 
 
 def _get_module_scenarios_reduction(
-    module: Literal["energy", "materials", "cooling"],
+    module: Literal["energy", "materials", "cooling", "dac"],
     energy_map_df: pd.DataFrame,
     tech_map_df: pd.DataFrame,
 ) -> pd.DataFrame:
@@ -160,7 +160,7 @@ def _get_module_scenarios_reduction(
 
 
 def _get_module_cost_reduction(
-    module: Literal["energy", "materials", "cooling"],
+    module: Literal["energy", "materials", "cooling", "dac"],
     energy_map_df: pd.DataFrame,
     tech_map_df: pd.DataFrame,
 ) -> pd.DataFrame:
@@ -294,7 +294,7 @@ def _get_module_cost_reduction(
 
 # create function to get technology reduction scenarios data
 def get_technology_reduction_scenarios_data(
-    first_year: int, module: Literal["energy", "materials", "cooling"]
+    first_year: int, module: Literal["energy", "materials", "cooling", "dac"]
 ) -> pd.DataFrame:
     # Get full list of technologies from mapping
     tech_map = energy_map = get_raw_technology_mapping("energy")
diff --git a/message_ix_models/tools/costs/regional_differentiation.py b/message_ix_models/tools/costs/regional_differentiation.py
index 8957475d9..aec47d0e4 100644
--- a/message_ix_models/tools/costs/regional_differentiation.py
+++ b/message_ix_models/tools/costs/regional_differentiation.py
@@ -172,7 +172,7 @@ def get_intratec_data() -> pd.DataFrame:
 
 
 def get_raw_technology_mapping(
-    module: Literal["energy", "materials", "cooling"],
+    module: Literal["energy", "materials", "cooling", "dac"],
 ) -> pd.DataFrame:
     """Retrieve a technology mapping for `module`.
 
@@ -235,7 +235,7 @@ def subset_module_map(raw_map):
 
 
 def adjust_technology_mapping(
-    module: Literal["energy", "materials", "cooling"],
+    module: Literal["energy", "materials", "cooling", "dac"],
 ) -> pd.DataFrame:
     """Adjust technology mapping based on sources and assumptions.