diff --git a/signals/cluster_detector.py b/signals/cluster_detector.py
index 7f3a172..cb3811f 100644
--- a/signals/cluster_detector.py
+++ b/signals/cluster_detector.py
@@ -1,9 +1,11 @@
+from typing import Optional
+
 from db.db import get_recent_buys_for_ticker
 import config
 
 
-def detect_cluster(ticker: str) -> dict:
-    buys = get_recent_buys_for_ticker(ticker, config.CLUSTER_WINDOW_DAYS)
+def detect_cluster(ticker: str, as_of_date: Optional[str] = None) -> dict:
+    buys = get_recent_buys_for_ticker(ticker, config.CLUSTER_WINDOW_DAYS, as_of_date=as_of_date)
     unique_insiders = {b["insider_name"] for b in buys}
     total_value = sum(b["total_value"] or 0 for b in buys)
     return {
diff --git a/signals/filter_engine.py b/signals/filter_engine.py
index ad020fb..fcca4ef 100644
--- a/signals/filter_engine.py
+++ b/signals/filter_engine.py
@@ -25,10 +25,16 @@ def _score(total_value: float, role: str, cluster_size: int) -> float:
     return base * math.log(total_value) * cluster_mult
 
 
-def process_filing(filing: dict) -> Optional[dict]:
+def process_filing(filing: dict, as_of_date: Optional[str] = None) -> Optional[dict]:
     if filing.get("flag") != "A":
         return None
 
+    # Only open market purchases (P) or non-coded buys; exclude option exercises (X), grants (A), etc.
+    tx_code = filing.get("tx_code", "")
+    if tx_code and tx_code not in ("P", ""):
+        logger.debug(f"Skipping non-open-market tx_code={tx_code}: {filing['accession_number']}")
+        return None
+
     if filing.get("is_10b51"):
         logger.debug(f"Skipping 10b5-1 filing: {filing['accession_number']}")
         return None
@@ -39,10 +45,10 @@ def process_filing(filing: dict) -> Optional[dict]:
         return None
 
     ticker = filing.get("ticker", "")
-    if not ticker:
+    if not ticker or ticker.upper() in ("NONE", "N/A", "NA"):
         return None
 
-    cluster_info = detect_cluster(ticker)
+    cluster_info = detect_cluster(ticker, as_of_date=as_of_date)
     cluster_size = cluster_info["cluster_size"]
     total_cluster_value = cluster_info["total_cluster_value"]