diff --git a/scripts/research/trackD_timing.py b/scripts/research/trackD_timing.py
index 4b67568..e52ff6b 100644
--- a/scripts/research/trackD_timing.py
+++ b/scripts/research/trackD_timing.py
@@ -51,7 +51,8 @@ def resample_ohlc(df: pd.DataFrame, rule: str) -> pd.DataFrame:
         {"open": "first", "high": "max", "low": "min", "close": "last", "volume": "sum"})
     out = out.dropna(subset=["open"])
     out["datetime"] = out.index
-    out["timestamp"] = (out.index.view("int64") // 1_000_000)
+    epoch = pd.Timestamp("1970-01-01", tz="UTC")
+    out["timestamp"] = ((out.index - epoch) // pd.Timedelta(milliseconds=1)).astype("int64")
     return out.reset_index(drop=True)[["timestamp", "open", "high", "low", "close", "volume", "datetime"]]