diff --git a/.gitignore b/.gitignore
index 63fd5cf61..26f8fd3e8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@
 .venv/
 __pycache__/
 .envrc
+.env.nu
 coverage/
 .coverage
 *.csv
diff --git a/applications/portfoliomanager/src/portfoliomanager/alpaca_client.py b/applications/portfoliomanager/src/portfoliomanager/alpaca_client.py
index 5ab4be2f8..1007b6daa 100644
--- a/applications/portfoliomanager/src/portfoliomanager/alpaca_client.py
+++ b/applications/portfoliomanager/src/portfoliomanager/alpaca_client.py
@@ -160,12 +160,46 @@ def open_position(
     def close_position(
         self,
         ticker: str,
-    ) -> None:
-        self.trading_client.close_position(
-            symbol_or_asset_id=ticker.upper(),
-            close_options=ClosePositionRequest(
-                percentage="100",
-            ),
-        )
+    ) -> bool:
+        """Close a position for the given ticker.
 
-        time.sleep(self.rate_limit_sleep)
+        Returns True if position was closed, False if position didn't exist.
+        """
+        try:
+            self.trading_client.close_position(
+                symbol_or_asset_id=ticker.upper(),
+                close_options=ClosePositionRequest(
+                    percentage="100",
+                ),
+            )
+            time.sleep(self.rate_limit_sleep)
+        except APIError as e:
+            # Prefer structured information from the Alpaca API when available,
+            # and fall back to matching documented error message fragments for
+            # backwards compatibility.
+            status_code = getattr(e, "status_code", None)
+            error_code = getattr(e, "code", None)
+            error_message = getattr(e, "message", None)
+            error_str = (
+                str(error_message) if error_message is not None else str(e)
+            ).lower()
+
+            # Known Alpaca behaviours when closing a non-existent position:
+            # - HTTP 404 Not Found
+            # - Specific error_code values (e.g. "position_not_found")
+            # - Error messages containing "position not found"
+            http_not_found = 404
+            position_not_found = (
+                status_code == http_not_found
+                or error_code in {"position_not_found"}
+                or "position not found" in error_str
+                or "position does not exist" in error_str
+            )
+            if position_not_found:
+                logger.info(
+                    "Position already closed or does not exist",
+                    ticker=ticker,
+                )
+                return False
+            raise
+        return True
diff --git a/applications/portfoliomanager/src/portfoliomanager/risk_management.py b/applications/portfoliomanager/src/portfoliomanager/risk_management.py
index fa2aa928c..66ce8b7f7 100644
--- a/applications/portfoliomanager/src/portfoliomanager/risk_management.py
+++ b/applications/portfoliomanager/src/portfoliomanager/risk_management.py
@@ -83,6 +83,18 @@ def add_portfolio_performance_columns(
     prior_predictions = prior_predictions.clone()
     prior_equity_bars = prior_equity_bars.clone()
 
+    # Ensure timestamp columns have matching types for joins and comparisons.
+    # Timestamps may arrive as i64 (from JSON integer serialization) or f64 (from
+    # Python float conversion). Unconditional casting to Float64 is simpler and
+    # more robust than checking dtypes, and the performance cost is negligible.
+    prior_portfolio = prior_portfolio.with_columns(pl.col("timestamp").cast(pl.Float64))
+    prior_predictions = prior_predictions.with_columns(
+        pl.col("timestamp").cast(pl.Float64)
+    )
+    prior_equity_bars = prior_equity_bars.with_columns(
+        pl.col("timestamp").cast(pl.Float64)
+    )
+
     prior_portfolio_predictions = prior_portfolio.join(
         other=prior_predictions,
         on=["ticker", "timestamp"],
diff --git a/applications/portfoliomanager/src/portfoliomanager/server.py b/applications/portfoliomanager/src/portfoliomanager/server.py
index 4cbb36c33..baae81efb 100644
--- a/applications/portfoliomanager/src/portfoliomanager/server.py
+++ b/applications/portfoliomanager/src/portfoliomanager/server.py
@@ -173,17 +173,31 @@ async def create_portfolio() -> Response:  # noqa: PLR0911, PLR0912, PLR0915, C9
     close_results = []
     for close_position in close_positions:
         try:
-            alpaca_client.close_position(
+            was_closed = alpaca_client.close_position(
                 ticker=close_position["ticker"],
             )
-            logger.info("Closed position", ticker=close_position["ticker"])
-            close_results.append(
-                {
-                    "ticker": close_position["ticker"],
-                    "action": "close",
-                    "status": "success",
-                }
-            )
+            if was_closed:
+                logger.info("Closed position", ticker=close_position["ticker"])
+                close_results.append(
+                    {
+                        "ticker": close_position["ticker"],
+                        "action": "close",
+                        "status": "success",
+                    }
+                )
+            else:
+                logger.info(
+                    "Position already closed or did not exist",
+                    ticker=close_position["ticker"],
+                )
+                close_results.append(
+                    {
+                        "ticker": close_position["ticker"],
+                        "action": "close",
+                        "status": "skipped",
+                        "reason": "position_not_found",
+                    }
+                )
         except Exception as e:
             logger.exception(
                 "Failed to close position",
diff --git a/tools/sync_equity_categories.py b/tools/sync_equity_categories.py
index 5c988c8bb..e4a6184b1 100644
--- a/tools/sync_equity_categories.py
+++ b/tools/sync_equity_categories.py
@@ -73,6 +73,9 @@ def extract_categories(tickers: list[dict]) -> pl.DataFrame:
     rows = []
     for ticker_data in tickers:
         ticker = ticker_data.get("ticker", "")
+        # Skip entries with empty or missing ticker values
+        if not ticker:
+            continue
         # Filter for Common Stock and all ADR types
         if ticker_data.get("type") not in EQUITY_TYPES:
             continue