diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 000000000..33d3885b2
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2026-01-30 - Hidden Complexity in Properties
+**Learning:** Properties like `self.timeframes` in `freqtrade`'s Exchange class may regenerate lists/dicts on every access. Using them in tight loops causes significant overhead ($O(N)$ lookup + allocation) compared to cached variables.
+**Action:** Always inspect property implementations before using them in loops. Hoist invariant property accesses out of loops and convert to sets for membership tests.
diff --git a/freqtrade/exchange/exchange.py b/freqtrade/exchange/exchange.py
index ac19696fa..d236b18d3 100644
--- a/freqtrade/exchange/exchange.py
+++ b/freqtrade/exchange/exchange.py
@@ -2732,6 +2732,10 @@ class Exchange:
         """
         input_coroutines: list[Coroutine[Any, Any, OHLCVResponse]] = []
         cached_pairs = []
+        # optimization: cache timeframes as a set outside the loop to avoid repeated property access
+        # and linear search
+        available_timeframes = set(self.timeframes)
+
         for pair, timeframe, candle_type in set(pair_list):
             if candle_type == CandleType.FUNDING_RATE and timeframe != (
                 ff_tf := self.get_option("funding_fee_timeframe")
@@ -2743,7 +2747,7 @@ class Exchange:
                     f"downloading {ff_tf} instead."
                 )
                 timeframe = ff_tf
-            invalid_timeframe = timeframe not in self.timeframes and candle_type in (
+            invalid_timeframe = timeframe not in available_timeframes and candle_type in (
                 CandleType.SPOT,
                 CandleType.FUTURES,
             )