diff --git a/src/fxhnt/adapters/orchestration/assets.py b/src/fxhnt/adapters/orchestration/assets.py
index 87130c5..02e1d39 100644
--- a/src/fxhnt/adapters/orchestration/assets.py
+++ b/src/fxhnt/adapters/orchestration/assets.py
@@ -51,7 +51,7 @@ def crypto_bars(context: AssetExecutionContext) -> int:
     return n
 
 
-@asset
+@asset(deps=[crypto_bars])   # serialize after crypto_bars: DuckDB is single-writer (one lock on warehouse.duckdb)
 def futures_bars(context: AssetExecutionContext) -> int:
     """Bronze → silver → warehouse: ingest continuous front-month futures arrays.